fs/ocfs2/dlm/dlmmaster.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dlmmod.c
   5  *
   6  * standalone DLM module
   7  *
   8  * Copyright (C) 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  *
  25  */
  26
  27
  28 #include <linux/module.h>
  29 #include <linux/fs.h>
  30 #include <linux/types.h>
  31 #include <linux/slab.h>
  32 #include <linux/highmem.h>
  33 #include <linux/utsname.h>
  34 #include <linux/init.h>
  35 #include <linux/sysctl.h>
  36 #include <linux/random.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/socket.h>
  39 #include <linux/inet.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/delay.h>
  42
  43
  44 #include "cluster/heartbeat.h"
  45 #include "cluster/nodemanager.h"
  46 #include "cluster/tcp.h"
  47
  48 #include "dlmapi.h"
  49 #include "dlmcommon.h"
  50 #include "dlmdomain.h"
  51
  52 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
  53 #include "cluster/masklog.h"
  54
  55 enum dlm_mle_type {
  56         DLM_MLE_BLOCK,
  57         DLM_MLE_MASTER,
  58         DLM_MLE_MIGRATION
  59 };
  60
  61 struct dlm_lock_name
  62 {
  63         u8 len;
  64         u8 name[DLM_LOCKID_NAME_MAX];
  65 };
  66
  67 struct dlm_master_list_entry
  68 {
  69         struct list_head list;
  70         struct list_head hb_events;
  71         struct dlm_ctxt *dlm;
  72         spinlock_t spinlock;
  73         wait_queue_head_t wq;
  74         atomic_t woken;
  75         struct kref mle_refs;
  76         int inuse;
  77         unsigned long maybe_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
  78         unsigned long vote_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
  79         unsigned long response_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
  80         unsigned long node_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
  81         u8 master;
  82         u8 new_master;
  83         enum dlm_mle_type type;
  84         struct o2hb_callback_func mle_hb_up;
  85         struct o2hb_callback_func mle_hb_down;
  86         union {
  87                 struct dlm_lock_resource *res;
  88                 struct dlm_lock_name name;
  89         } u;
  90 };
  91
  92 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
  93                               struct dlm_master_list_entry *mle,
  94                               struct o2nm_node *node,
  95                               int idx);
  96 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
  97                             struct dlm_master_list_entry *mle,
  98                             struct o2nm_node *node,
  99                             int idx);
 100
 101 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
 102 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
 103                                 struct dlm_lock_resource *res,
 104                                 void *nodemap, u32 flags);
 105
 106 static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
 107                                 struct dlm_master_list_entry *mle,
 108                                 const char *name,
 109                                 unsigned int namelen)
 110 {
 111         struct dlm_lock_resource *res;
 112
 113         if (dlm != mle->dlm)
 114                 return 0;
 115
 116         if (mle->type == DLM_MLE_BLOCK ||
 117             mle->type == DLM_MLE_MIGRATION) {
 118                 if (namelen != mle->u.name.len ||
 119                     memcmp(name, mle->u.name.name, namelen)!=0)
 120                         return 0;
 121         } else {
 122                 res = mle->u.res;
 123                 if (namelen != res->lockname.len ||
 124                     memcmp(res->lockname.name, name, namelen) != 0)
 125                         return 0;
 126         }
 127         return 1;
 128 }
 129
 130 #define dlm_print_nodemap(m)  _dlm_print_nodemap(m,#m)
 131 static void _dlm_print_nodemap(unsigned long *map, const char *mapname)
 132 {
 133         int i;
 134         printk("%s=[ ", mapname);
 135         for (i=0; i<O2NM_MAX_NODES; i++)
 136                 if (test_bit(i, map))
 137                         printk("%d ", i);
 138         printk("]");
 139 }
 140
 141 static void dlm_print_one_mle(struct dlm_master_list_entry *mle)
 142 {
 143         int refs;
 144         char *type;
 145         char attached;
 146         u8 master;
 147         unsigned int namelen;
 148         const char *name;
 149         struct kref *k;
 150         unsigned long *maybe = mle->maybe_map,
 151                       *vote = mle->vote_map,
 152                       *resp = mle->response_map,
 153                       *node = mle->node_map;
 154
 155         k = &mle->mle_refs;
 156         if (mle->type == DLM_MLE_BLOCK)
 157                 type = "BLK";
 158         else if (mle->type == DLM_MLE_MASTER)
 159                 type = "MAS";
 160         else
 161                 type = "MIG";
 162         refs = atomic_read(&k->refcount);
 163         master = mle->master;
 164         attached = (list_empty(&mle->hb_events) ? 'N' : 'Y');
 165
 166         if (mle->type != DLM_MLE_MASTER) {
 167                 namelen = mle->u.name.len;
 168                 name = mle->u.name.name;
 169         } else {
 170                 namelen = mle->u.res->lockname.len;
 171                 name = mle->u.res->lockname.name;
 172         }
 173
 174         mlog(ML_NOTICE, "%.*s: %3s refs=%3d mas=%3u new=%3u evt=%c inuse=%d ",
 175                   namelen, name, type, refs, master, mle->new_master, attached,
 176                   mle->inuse);
 177         dlm_print_nodemap(maybe);
 178         printk(", ");
 179         dlm_print_nodemap(vote);
 180         printk(", ");
 181         dlm_print_nodemap(resp);
 182         printk(", ");
 183         dlm_print_nodemap(node);
 184         printk(", ");
 185         printk("\n");
 186 }
 187
 188 #if 0
 189 /* Code here is included but defined out as it aids debugging */
 190
 191 static void dlm_dump_mles(struct dlm_ctxt *dlm)
 192 {
 193         struct dlm_master_list_entry *mle;
 194         struct list_head *iter;
 195
 196         mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
 197         spin_lock(&dlm->master_lock);
 198         list_for_each(iter, &dlm->master_list) {
 199                 mle = list_entry(iter, struct dlm_master_list_entry, list);
 200                 dlm_print_one_mle(mle);
 201         }
 202         spin_unlock(&dlm->master_lock);
 203 }
 204
 205 int dlm_dump_all_mles(const char __user *data, unsigned int len)
 206 {
 207         struct list_head *iter;
 208         struct dlm_ctxt *dlm;
 209
 210         spin_lock(&dlm_domain_lock);
 211         list_for_each(iter, &dlm_domains) {
 212                 dlm = list_entry (iter, struct dlm_ctxt, list);
 213                 mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
 214                 dlm_dump_mles(dlm);
 215         }
 216         spin_unlock(&dlm_domain_lock);
 217         return len;
 218 }
 219 EXPORT_SYMBOL_GPL(dlm_dump_all_mles);
 220
 221 #endif  /*  0  */
 222
 223
 224 static struct kmem_cache *dlm_mle_cache = NULL;
 225
 226
 227 static void dlm_mle_release(struct kref *kref);
 228 static void dlm_init_mle(struct dlm_master_list_entry *mle,
 229                         enum dlm_mle_type type,
 230                         struct dlm_ctxt *dlm,
 231                         struct dlm_lock_resource *res,
 232                         const char *name,
 233                         unsigned int namelen);
 234 static void dlm_put_mle(struct dlm_master_list_entry *mle);
 235 static void __dlm_put_mle(struct dlm_master_list_entry *mle);
 236 static int dlm_find_mle(struct dlm_ctxt *dlm,
 237                         struct dlm_master_list_entry **mle,
 238                         char *name, unsigned int namelen);
 239
 240 static int dlm_do_master_request(struct dlm_lock_resource *res,
 241                                  struct dlm_master_list_entry *mle, int to);
 242
 243
 244 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
 245                                      struct dlm_lock_resource *res,
 246                                      struct dlm_master_list_entry *mle,
 247                                      int *blocked);
 248 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
 249                                     struct dlm_lock_resource *res,
 250                                     struct dlm_master_list_entry *mle,
 251                                     int blocked);
 252 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
 253                                  struct dlm_lock_resource *res,
 254                                  struct dlm_master_list_entry *mle,
 255                                  struct dlm_master_list_entry **oldmle,
 256                                  const char *name, unsigned int namelen,
 257                                  u8 new_master, u8 master);
 258
 259 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
 260                                     struct dlm_lock_resource *res);
 261 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
 262                                       struct dlm_lock_resource *res);
 263 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
 264                                        struct dlm_lock_resource *res,
 265                                        u8 target);
 266 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
 267                                        struct dlm_lock_resource *res);
 268
 269
 270 int dlm_is_host_down(int errno)
 271 {
 272         switch (errno) {
 273                 case -EBADF:
 274                 case -ECONNREFUSED:
 275                 case -ENOTCONN:
 276                 case -ECONNRESET:
 277                 case -EPIPE:
 278                 case -EHOSTDOWN:
 279                 case -EHOSTUNREACH:
 280                 case -ETIMEDOUT:
 281                 case -ECONNABORTED:
 282                 case -ENETDOWN:
 283                 case -ENETUNREACH:
 284                 case -ENETRESET:
 285                 case -ESHUTDOWN:
 286                 case -ENOPROTOOPT:
 287                 case -EINVAL:   /* if returned from our tcp code,
 288                                    this means there is no socket */
 289                         return 1;
 290         }
 291         return 0;
 292 }
 293
 294
 295 /*
 296  * MASTER LIST FUNCTIONS
 297  */
 298
 299
 300 /*
 301  * regarding master list entries and heartbeat callbacks:
 302  *
 303  * in order to avoid sleeping and allocation that occurs in
 304  * heartbeat, master list entries are simply attached to the
 305  * dlm's established heartbeat callbacks.  the mle is attached
 306  * when it is created, and since the dlm->spinlock is held at
 307  * that time, any heartbeat event will be properly discovered
 308  * by the mle.  the mle needs to be detached from the
 309  * dlm->mle_hb_events list as soon as heartbeat events are no
 310  * longer useful to the mle, and before the mle is freed.
 311  *
 312  * as a general rule, heartbeat events are no longer needed by
 313  * the mle once an "answer" regarding the lock master has been
 314  * received.
 315  */
 316 static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
 317                                               struct dlm_master_list_entry *mle)
 318 {
 319         assert_spin_locked(&dlm->spinlock);
 320
 321         list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
 322 }
 323
 324
 325 static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
 326                                               struct dlm_master_list_entry *mle)
 327 {
 328         if (!list_empty(&mle->hb_events))
 329                 list_del_init(&mle->hb_events);
 330 }
 331
 332
 333 static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
 334                                             struct dlm_master_list_entry *mle)
 335 {
 336         spin_lock(&dlm->spinlock);
 337         __dlm_mle_detach_hb_events(dlm, mle);
 338         spin_unlock(&dlm->spinlock);
 339 }
 340
 341 static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
 342 {
 343         struct dlm_ctxt *dlm;
 344         dlm = mle->dlm;
 345
 346         assert_spin_locked(&dlm->spinlock);
 347         assert_spin_locked(&dlm->master_lock);
 348         mle->inuse++;
 349         kref_get(&mle->mle_refs);
 350 }
 351
 352 static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
 353 {
 354         struct dlm_ctxt *dlm;
 355         dlm = mle->dlm;
 356
 357         spin_lock(&dlm->spinlock);
 358         spin_lock(&dlm->master_lock);
 359         mle->inuse--;
 360         __dlm_put_mle(mle);
 361         spin_unlock(&dlm->master_lock);
 362         spin_unlock(&dlm->spinlock);
 363
 364 }
 365
 366 /* remove from list and free */
 367 static void __dlm_put_mle(struct dlm_master_list_entry *mle)
 368 {
 369         struct dlm_ctxt *dlm;
 370         dlm = mle->dlm;
 371
 372         assert_spin_locked(&dlm->spinlock);
 373         assert_spin_locked(&dlm->master_lock);
 374         if (!atomic_read(&mle->mle_refs.refcount)) {
 375                 /* this may or may not crash, but who cares.
 376                  * it's a BUG. */
 377                 mlog(ML_ERROR, "bad mle: %p\n", mle);
 378                 dlm_print_one_mle(mle);
 379                 BUG();
 380         } else
 381                 kref_put(&mle->mle_refs, dlm_mle_release);
 382 }
 383
 384
 385 /* must not have any spinlocks coming in */
 386 static void dlm_put_mle(struct dlm_master_list_entry *mle)
 387 {
 388         struct dlm_ctxt *dlm;
 389         dlm = mle->dlm;
 390
 391         spin_lock(&dlm->spinlock);
 392         spin_lock(&dlm->master_lock);
 393         __dlm_put_mle(mle);
 394         spin_unlock(&dlm->master_lock);
 395         spin_unlock(&dlm->spinlock);
 396 }
 397
 398 static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
 399 {
 400         kref_get(&mle->mle_refs);
 401 }
 402
 403 static void dlm_init_mle(struct dlm_master_list_entry *mle,
 404                         enum dlm_mle_type type,
 405                         struct dlm_ctxt *dlm,
 406                         struct dlm_lock_resource *res,
 407                         const char *name,
 408                         unsigned int namelen)
 409 {
 410         assert_spin_locked(&dlm->spinlock);
 411
 412         mle->dlm = dlm;
 413         mle->type = type;
 414         INIT_LIST_HEAD(&mle->list);
 415         INIT_LIST_HEAD(&mle->hb_events);
 416         memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
 417         spin_lock_init(&mle->spinlock);
 418         init_waitqueue_head(&mle->wq);
 419         atomic_set(&mle->woken, 0);
 420         kref_init(&mle->mle_refs);
 421         memset(mle->response_map, 0, sizeof(mle->response_map));
 422         mle->master = O2NM_MAX_NODES;
 423         mle->new_master = O2NM_MAX_NODES;
 424         mle->inuse = 0;
 425
 426         if (mle->type == DLM_MLE_MASTER) {
 427                 BUG_ON(!res);
 428                 mle->u.res = res;
 429         } else if (mle->type == DLM_MLE_BLOCK) {
 430                 BUG_ON(!name);
 431                 memcpy(mle->u.name.name, name, namelen);
 432                 mle->u.name.len = namelen;
 433         } else /* DLM_MLE_MIGRATION */ {
 434                 BUG_ON(!name);
 435                 memcpy(mle->u.name.name, name, namelen);
 436                 mle->u.name.len = namelen;
 437         }
 438
 439         /* copy off the node_map and register hb callbacks on our copy */
 440         memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
 441         memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
 442         clear_bit(dlm->node_num, mle->vote_map);
 443         clear_bit(dlm->node_num, mle->node_map);
 444
 445         /* attach the mle to the domain node up/down events */
 446         __dlm_mle_attach_hb_events(dlm, mle);
 447 }
 448
 449
 450 /* returns 1 if found, 0 if not */
 451 static int dlm_find_mle(struct dlm_ctxt *dlm,
 452                         struct dlm_master_list_entry **mle,
 453                         char *name, unsigned int namelen)
 454 {
 455         struct dlm_master_list_entry *tmpmle;
 456         struct list_head *iter;
 457
 458         assert_spin_locked(&dlm->master_lock);
 459
 460         list_for_each(iter, &dlm->master_list) {
 461                 tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
 462                 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
 463                         continue;
 464                 dlm_get_mle(tmpmle);
 465                 *mle = tmpmle;
 466                 return 1;
 467         }
 468         return 0;
 469 }
 470
 471 void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
 472 {
 473         struct dlm_master_list_entry *mle;
 474         struct list_head *iter;
 475
 476         assert_spin_locked(&dlm->spinlock);
 477
 478         list_for_each(iter, &dlm->mle_hb_events) {
 479                 mle = list_entry(iter, struct dlm_master_list_entry,
 480                                  hb_events);
 481                 if (node_up)
 482                         dlm_mle_node_up(dlm, mle, NULL, idx);
 483                 else
 484                         dlm_mle_node_down(dlm, mle, NULL, idx);
 485         }
 486 }
 487
 488 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
 489                               struct dlm_master_list_entry *mle,
 490                               struct o2nm_node *node, int idx)
 491 {
 492         spin_lock(&mle->spinlock);
 493
 494         if (!test_bit(idx, mle->node_map))
 495                 mlog(0, "node %u already removed from nodemap!\n", idx);
 496         else
 497                 clear_bit(idx, mle->node_map);
 498
 499         spin_unlock(&mle->spinlock);
 500 }
 501
 502 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
 503                             struct dlm_master_list_entry *mle,
 504                             struct o2nm_node *node, int idx)
 505 {
 506         spin_lock(&mle->spinlock);
 507
 508         if (test_bit(idx, mle->node_map))
 509                 mlog(0, "node %u already in node map!\n", idx);
 510         else
 511                 set_bit(idx, mle->node_map);
 512
 513         spin_unlock(&mle->spinlock);
 514 }
 515
 516
 517 int dlm_init_mle_cache(void)
 518 {
 519         dlm_mle_cache = kmem_cache_create("dlm_mle_cache",
 520                                           sizeof(struct dlm_master_list_entry),
 521                                           0, SLAB_HWCACHE_ALIGN,
 522                                           NULL, NULL);
 523         if (dlm_mle_cache == NULL)
 524                 return -ENOMEM;
 525         return 0;
 526 }
 527
 528 void dlm_destroy_mle_cache(void)
 529 {
 530         if (dlm_mle_cache)
 531                 kmem_cache_destroy(dlm_mle_cache);
 532 }
 533
 534 static void dlm_mle_release(struct kref *kref)
 535 {
 536         struct dlm_master_list_entry *mle;
 537         struct dlm_ctxt *dlm;
 538
 539         mlog_entry_void();
 540
 541         mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
 542         dlm = mle->dlm;
 543
 544         if (mle->type != DLM_MLE_MASTER) {
 545                 mlog(0, "calling mle_release for %.*s, type %d\n",
 546                      mle->u.name.len, mle->u.name.name, mle->type);
 547         } else {
 548                 mlog(0, "calling mle_release for %.*s, type %d\n",
 549                      mle->u.res->lockname.len,
 550                      mle->u.res->lockname.name, mle->type);
 551         }
 552         assert_spin_locked(&dlm->spinlock);
 553         assert_spin_locked(&dlm->master_lock);
 554
 555         /* remove from list if not already */
 556         if (!list_empty(&mle->list))
 557                 list_del_init(&mle->list);
 558
 559         /* detach the mle from the domain node up/down events */
 560         __dlm_mle_detach_hb_events(dlm, mle);
 561
 562         /* NOTE: kfree under spinlock here.
 563          * if this is bad, we can move this to a freelist. */
 564         kmem_cache_free(dlm_mle_cache, mle);
 565 }
 566
 567
 568 /*
 569  * LOCK RESOURCE FUNCTIONS
 570  */
 571
 572 static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
 573                                   struct dlm_lock_resource *res,
 574                                   u8 owner)
 575 {
 576         assert_spin_locked(&res->spinlock);
 577
 578         mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
 579
 580         if (owner == dlm->node_num)
 581                 atomic_inc(&dlm->local_resources);
 582         else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
 583                 atomic_inc(&dlm->unknown_resources);
 584         else
 585                 atomic_inc(&dlm->remote_resources);
 586
 587         res->owner = owner;
 588 }
 589
 590 void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
 591                               struct dlm_lock_resource *res, u8 owner)
 592 {
 593         assert_spin_locked(&res->spinlock);
 594
 595         if (owner == res->owner)
 596                 return;
 597
 598         if (res->owner == dlm->node_num)
 599                 atomic_dec(&dlm->local_resources);
 600         else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
 601                 atomic_dec(&dlm->unknown_resources);
 602         else
 603                 atomic_dec(&dlm->remote_resources);
 604
 605         dlm_set_lockres_owner(dlm, res, owner);
 606 }
 607
 608
 609 static void dlm_lockres_release(struct kref *kref)
 610 {
 611         struct dlm_lock_resource *res;
 612
 613         res = container_of(kref, struct dlm_lock_resource, refs);
 614
 615         /* This should not happen -- all lockres' have a name
 616          * associated with them at init time. */
 617         BUG_ON(!res->lockname.name);
 618
 619         mlog(0, "destroying lockres %.*s\n", res->lockname.len,
 620              res->lockname.name);
 621
 622         if (!hlist_unhashed(&res->hash_node) ||
 623             !list_empty(&res->granted) ||
 624             !list_empty(&res->converting) ||
 625             !list_empty(&res->blocked) ||
 626             !list_empty(&res->dirty) ||
 627             !list_empty(&res->recovering) ||
 628             !list_empty(&res->purge)) {
 629                 mlog(ML_ERROR,
 630                      "Going to BUG for resource %.*s."
 631                      "  We're on a list! [%c%c%c%c%c%c%c]\n",
 632                      res->lockname.len, res->lockname.name,
 633                      !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
 634                      !list_empty(&res->granted) ? 'G' : ' ',
 635                      !list_empty(&res->converting) ? 'C' : ' ',
 636                      !list_empty(&res->blocked) ? 'B' : ' ',
 637                      !list_empty(&res->dirty) ? 'D' : ' ',
 638                      !list_empty(&res->recovering) ? 'R' : ' ',
 639                      !list_empty(&res->purge) ? 'P' : ' ');
 640
 641                 dlm_print_one_lock_resource(res);
 642         }
 643
 644         /* By the time we're ready to blow this guy away, we shouldn't
 645          * be on any lists. */
 646         BUG_ON(!hlist_unhashed(&res->hash_node));
 647         BUG_ON(!list_empty(&res->granted));
 648         BUG_ON(!list_empty(&res->converting));
 649         BUG_ON(!list_empty(&res->blocked));
 650         BUG_ON(!list_empty(&res->dirty));
 651         BUG_ON(!list_empty(&res->recovering));
 652         BUG_ON(!list_empty(&res->purge));
 653
 654         kfree(res->lockname.name);
 655
 656         kfree(res);
 657 }
 658
 659 void dlm_lockres_put(struct dlm_lock_resource *res)
 660 {
 661         kref_put(&res->refs, dlm_lockres_release);
 662 }
 663
 664 static void dlm_init_lockres(struct dlm_ctxt *dlm,
 665                              struct dlm_lock_resource *res,
 666                              const char *name, unsigned int namelen)
 667 {
 668         char *qname;
 669
 670         /* If we memset here, we lose our reference to the kmalloc'd
 671          * res->lockname.name, so be sure to init every field
 672          * correctly! */
 673
 674         qname = (char *) res->lockname.name;
 675         memcpy(qname, name, namelen);
 676
 677         res->lockname.len = namelen;
 678         res->lockname.hash = dlm_lockid_hash(name, namelen);
 679
 680         init_waitqueue_head(&res->wq);
 681         spin_lock_init(&res->spinlock);
 682         INIT_HLIST_NODE(&res->hash_node);
 683         INIT_LIST_HEAD(&res->granted);
 684         INIT_LIST_HEAD(&res->converting);
 685         INIT_LIST_HEAD(&res->blocked);
 686         INIT_LIST_HEAD(&res->dirty);
 687         INIT_LIST_HEAD(&res->recovering);
 688         INIT_LIST_HEAD(&res->purge);
 689         atomic_set(&res->asts_reserved, 0);
 690         res->migration_pending = 0;
 691         res->inflight_locks = 0;
 692
 693         kref_init(&res->refs);
 694
 695         /* just for consistency */
 696         spin_lock(&res->spinlock);
 697         dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
 698         spin_unlock(&res->spinlock);
 699
 700         res->state = DLM_LOCK_RES_IN_PROGRESS;
 701
 702         res->last_used = 0;
 703
 704         memset(res->lvb, 0, DLM_LVB_LEN);
 705         memset(res->refmap, 0, sizeof(res->refmap));
 706 }
 707
 708 struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
 709                                    const char *name,
 710                                    unsigned int namelen)
 711 {
 712         struct dlm_lock_resource *res;
 713
 714         res = kmalloc(sizeof(struct dlm_lock_resource), GFP_NOFS);
 715         if (!res)
 716                 return NULL;
 717
 718         res->lockname.name = kmalloc(namelen, GFP_NOFS);
 719         if (!res->lockname.name) {
 720                 kfree(res);
 721                 return NULL;
 722         }
 723
 724         dlm_init_lockres(dlm, res, name, namelen);
 725         return res;
 726 }
 727
 728 void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
 729                                    struct dlm_lock_resource *res,
 730                                    int new_lockres,
 731                                    const char *file,
 732                                    int line)
 733 {
 734         if (!new_lockres)
 735                 assert_spin_locked(&res->spinlock);
 736
 737         if (!test_bit(dlm->node_num, res->refmap)) {
 738                 BUG_ON(res->inflight_locks != 0);
 739                 dlm_lockres_set_refmap_bit(dlm->node_num, res);
 740         }
 741         res->inflight_locks++;
 742         mlog(0, "%s:%.*s: inflight++: now %u\n",
 743              dlm->name, res->lockname.len, res->lockname.name,
 744              res->inflight_locks);
 745 }
 746
 747 void __dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
 748                                    struct dlm_lock_resource *res,
 749                                    const char *file,
 750                                    int line)
 751 {
 752         assert_spin_locked(&res->spinlock);
 753
 754         BUG_ON(res->inflight_locks == 0);
 755         res->inflight_locks--;
 756         mlog(0, "%s:%.*s: inflight--: now %u\n",
 757              dlm->name, res->lockname.len, res->lockname.name,
 758              res->inflight_locks);
 759         if (res->inflight_locks == 0)
 760                 dlm_lockres_clear_refmap_bit(dlm->node_num, res);
 761         wake_up(&res->wq);
 762 }
 763
 764 /*
 765  * lookup a lock resource by name.
 766  * may already exist in the hashtable.
 767  * lockid is null terminated
 768  *
 769  * if not, allocate enough for the lockres and for
 770  * the temporary structure used in doing the mastering.
 771  *
 772  * also, do a lookup in the dlm->master_list to see
 773  * if another node has begun mastering the same lock.
 774  * if so, there should be a block entry in there
 775  * for this name, and we should *not* attempt to master
 776  * the lock here.   need to wait around for that node
 777  * to assert_master (or die).
 778  *
 779  */
 780 struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
 781                                           const char *lockid,
 782                                           int namelen,
 783                                           int flags)
 784 {
 785         struct dlm_lock_resource *tmpres=NULL, *res=NULL;
 786         struct dlm_master_list_entry *mle = NULL;
 787         struct dlm_master_list_entry *alloc_mle = NULL;
 788         int blocked = 0;
 789         int ret, nodenum;
 790         struct dlm_node_iter iter;
 791         unsigned int hash;
 792         int tries = 0;
 793         int bit, wait_on_recovery = 0;
 794         int drop_inflight_if_nonlocal = 0;
 795
 796         BUG_ON(!lockid);
 797
 798         hash = dlm_lockid_hash(lockid, namelen);
 799
 800         mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
 801
 802 lookup:
 803         spin_lock(&dlm->spinlock);
 804         tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
 805         if (tmpres) {
 806                 int dropping_ref = 0;
 807
 808                 spin_lock(&tmpres->spinlock);
 809                 if (tmpres->owner == dlm->node_num) {
 810                         BUG_ON(tmpres->state & DLM_LOCK_RES_DROPPING_REF);
 811                         dlm_lockres_grab_inflight_ref(dlm, tmpres);
 812                 } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF)
 813                         dropping_ref = 1;
 814                 spin_unlock(&tmpres->spinlock);
 815                 spin_unlock(&dlm->spinlock);
 816
 817                 /* wait until done messaging the master, drop our ref to allow
 818                  * the lockres to be purged, start over. */
 819                 if (dropping_ref) {
 820                         spin_lock(&tmpres->spinlock);
 821                         __dlm_wait_on_lockres_flags(tmpres, DLM_LOCK_RES_DROPPING_REF);
 822                         spin_unlock(&tmpres->spinlock);
 823                         dlm_lockres_put(tmpres);
 824                         tmpres = NULL;
 825                         goto lookup;
 826                 }
 827
 828                 mlog(0, "found in hash!\n");
 829                 if (res)
 830                         dlm_lockres_put(res);
 831                 res = tmpres;
 832                 goto leave;
 833         }
 834
 835         if (!res) {
 836                 spin_unlock(&dlm->spinlock);
 837                 mlog(0, "allocating a new resource\n");
 838                 /* nothing found and we need to allocate one. */
 839                 alloc_mle = (struct dlm_master_list_entry *)
 840                         kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
 841                 if (!alloc_mle)
 842                         goto leave;
 843                 res = dlm_new_lockres(dlm, lockid, namelen);
 844                 if (!res)
 845                         goto leave;
 846                 goto lookup;
 847         }
 848
 849         mlog(0, "no lockres found, allocated our own: %p\n", res);
 850
 851         if (flags & LKM_LOCAL) {
 852                 /* caller knows it's safe to assume it's not mastered elsewhere
 853                  * DONE!  return right away */
 854                 spin_lock(&res->spinlock);
 855                 dlm_change_lockres_owner(dlm, res, dlm->node_num);
 856                 __dlm_insert_lockres(dlm, res);
 857                 dlm_lockres_grab_inflight_ref(dlm, res);
 858                 spin_unlock(&res->spinlock);
 859                 spin_unlock(&dlm->spinlock);
 860                 /* lockres still marked IN_PROGRESS */
 861                 goto wake_waiters;
 862         }
 863
 864         /* check master list to see if another node has started mastering it */
 865         spin_lock(&dlm->master_lock);
 866
 867         /* if we found a block, wait for lock to be mastered by another node */
 868         blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
 869         if (blocked) {
 870                 int mig;
 871                 if (mle->type == DLM_MLE_MASTER) {
 872                         mlog(ML_ERROR, "master entry for nonexistent lock!\n");
 873                         BUG();
 874                 }
 875                 mig = (mle->type == DLM_MLE_MIGRATION);
 876                 /* if there is a migration in progress, let the migration
 877                  * finish before continuing.  we can wait for the absence
 878                  * of the MIGRATION mle: either the migrate finished or
 879                  * one of the nodes died and the mle was cleaned up.
 880                  * if there is a BLOCK here, but it already has a master
 881                  * set, we are too late.  the master does not have a ref
 882                  * for us in the refmap.  detach the mle and drop it.
 883                  * either way, go back to the top and start over. */
 884                 if (mig || mle->master != O2NM_MAX_NODES) {
 885                         BUG_ON(mig && mle->master == dlm->node_num);
 886                         /* we arrived too late.  the master does not
 887                          * have a ref for us. retry. */
 888                         mlog(0, "%s:%.*s: late on %s\n",
 889                              dlm->name, namelen, lockid,
 890                              mig ?  "MIGRATION" : "BLOCK");
 891                         spin_unlock(&dlm->master_lock);
 892                         spin_unlock(&dlm->spinlock);
 893
 894                         /* master is known, detach */
 895                         if (!mig)
 896                                 dlm_mle_detach_hb_events(dlm, mle);
 897                         dlm_put_mle(mle);
 898                         mle = NULL;
 899                         /* this is lame, but we cant wait on either
 900                          * the mle or lockres waitqueue here */
 901                         if (mig)
 902                                 msleep(100);
 903                         goto lookup;
 904                 }
 905         } else {
 906                 /* go ahead and try to master lock on this node */
 907                 mle = alloc_mle;
 908                 /* make sure this does not get freed below */
 909                 alloc_mle = NULL;
 910                 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
 911                 set_bit(dlm->node_num, mle->maybe_map);
 912                 list_add(&mle->list, &dlm->master_list);
 913
 914                 /* still holding the dlm spinlock, check the recovery map
 915                  * to see if there are any nodes that still need to be
 916                  * considered.  these will not appear in the mle nodemap
 917                  * but they might own this lockres.  wait on them. */
 918                 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
 919                 if (bit < O2NM_MAX_NODES) {
 920                         mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
 921                              "recover before lock mastery can begin\n",
 922                              dlm->name, namelen, (char *)lockid, bit);
 923                         wait_on_recovery = 1;
 924                 }
 925         }
 926
 927         /* at this point there is either a DLM_MLE_BLOCK or a
 928          * DLM_MLE_MASTER on the master list, so it's safe to add the
 929          * lockres to the hashtable.  anyone who finds the lock will
 930          * still have to wait on the IN_PROGRESS. */
 931
 932         /* finally add the lockres to its hash bucket */
 933         __dlm_insert_lockres(dlm, res);
 934         /* since this lockres is new it doesnt not require the spinlock */
 935         dlm_lockres_grab_inflight_ref_new(dlm, res);
 936
 937         /* if this node does not become the master make sure to drop
 938          * this inflight reference below */
 939         drop_inflight_if_nonlocal = 1;
 940
 941         /* get an extra ref on the mle in case this is a BLOCK
 942          * if so, the creator of the BLOCK may try to put the last
 943          * ref at this time in the assert master handler, so we
 944          * need an extra one to keep from a bad ptr deref. */
 945         dlm_get_mle_inuse(mle);
 946         spin_unlock(&dlm->master_lock);
 947         spin_unlock(&dlm->spinlock);
 948
 949 redo_request:
 950         while (wait_on_recovery) {
 951                 /* any cluster changes that occurred after dropping the
 952                  * dlm spinlock would be detectable be a change on the mle,
 953                  * so we only need to clear out the recovery map once. */
 954                 if (dlm_is_recovery_lock(lockid, namelen)) {
 955                         mlog(ML_NOTICE, "%s: recovery map is not empty, but "
 956                              "must master $RECOVERY lock now\n", dlm->name);
 957                         if (!dlm_pre_master_reco_lockres(dlm, res))
 958                                 wait_on_recovery = 0;
 959                         else {
 960                                 mlog(0, "%s: waiting 500ms for heartbeat state "
 961                                     "change\n", dlm->name);
 962                                 msleep(500);
 963                         }
 964                         continue;
 965                 }
 966
 967                 dlm_kick_recovery_thread(dlm);
 968                 msleep(1000);
 969                 dlm_wait_for_recovery(dlm);
 970
 971                 spin_lock(&dlm->spinlock);
 972                 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
 973                 if (bit < O2NM_MAX_NODES) {
 974                         mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
 975                              "recover before lock mastery can begin\n",
 976                              dlm->name, namelen, (char *)lockid, bit);
 977                         wait_on_recovery = 1;
 978                 } else
 979                         wait_on_recovery = 0;
 980                 spin_unlock(&dlm->spinlock);
 981
 982                 if (wait_on_recovery)
 983                         dlm_wait_for_node_recovery(dlm, bit, 10000);
 984         }
 985
 986         /* must wait for lock to be mastered elsewhere */
 987         if (blocked)
 988                 goto wait;
 989
 990         ret = -EINVAL;
 991         dlm_node_iter_init(mle->vote_map, &iter);
 992         while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
 993                 ret = dlm_do_master_request(res, mle, nodenum);
 994                 if (ret < 0)
 995                         mlog_errno(ret);
 996                 if (mle->master != O2NM_MAX_NODES) {
 997                         /* found a master ! */
 998                         if (mle->master <= nodenum)
 999                                 break;
1000                         /* if our master request has not reached the master
1001                          * yet, keep going until it does.  this is how the
1002                          * master will know that asserts are needed back to
1003                          * the lower nodes. */
1004                         mlog(0, "%s:%.*s: requests only up to %u but master "
1005                              "is %u, keep going\n", dlm->name, namelen,
1006                              lockid, nodenum, mle->master);
1007                 }
1008         }
1009
1010 wait:
1011         /* keep going until the response map includes all nodes */
1012         ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
1013         if (ret < 0) {
1014                 wait_on_recovery = 1;
1015                 mlog(0, "%s:%.*s: node map changed, redo the "
1016                      "master request now, blocked=%d\n",
1017                      dlm->name, res->lockname.len,
1018                      res->lockname.name, blocked);
1019                 if (++tries > 20) {
1020                         mlog(ML_ERROR, "%s:%.*s: spinning on "
1021                              "dlm_wait_for_lock_mastery, blocked=%d\n",
1022                              dlm->name, res->lockname.len,
1023                              res->lockname.name, blocked);
1024                         dlm_print_one_lock_resource(res);
1025                         dlm_print_one_mle(mle);
1026                         tries = 0;
1027                 }
1028                 goto redo_request;
1029         }
1030
1031         mlog(0, "lockres mastered by %u\n", res->owner);
1032         /* make sure we never continue without this */
1033         BUG_ON(res->owner == O2NM_MAX_NODES);
1034
1035         /* master is known, detach if not already detached */
1036         dlm_mle_detach_hb_events(dlm, mle);
1037         dlm_put_mle(mle);
1038         /* put the extra ref */
1039         dlm_put_mle_inuse(mle);
1040
1041 wake_waiters:
1042         spin_lock(&res->spinlock);
1043         if (res->owner != dlm->node_num && drop_inflight_if_nonlocal)
1044                 dlm_lockres_drop_inflight_ref(dlm, res);
1045         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
1046         spin_unlock(&res->spinlock);
1047         wake_up(&res->wq);
1048
1049 leave:
1050         /* need to free the unused mle */
1051         if (alloc_mle)
1052                 kmem_cache_free(dlm_mle_cache, alloc_mle);
1053
1054         return res;
1055 }
1056
1057
1058 #define DLM_MASTERY_TIMEOUT_MS   5000
1059
1060 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
1061                                      struct dlm_lock_resource *res,
1062                                      struct dlm_master_list_entry *mle,
1063                                      int *blocked)
1064 {
1065         u8 m;
1066         int ret, bit;
1067         int map_changed, voting_done;
1068         int assert, sleep;
1069
1070 recheck:
1071         ret = 0;
1072         assert = 0;
1073
1074         /* check if another node has already become the owner */
1075         spin_lock(&res->spinlock);
1076         if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1077                 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1078                      res->lockname.len, res->lockname.name, res->owner);
1079                 spin_unlock(&res->spinlock);
1080                 /* this will cause the master to re-assert across
1081                  * the whole cluster, freeing up mles */
1082                 if (res->owner != dlm->node_num) {
1083                         ret = dlm_do_master_request(res, mle, res->owner);
1084                         if (ret < 0) {
1085                                 /* give recovery a chance to run */
1086                                 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1087                                 msleep(500);
1088                                 goto recheck;
1089                         }
1090                 }
1091                 ret = 0;
1092                 goto leave;
1093         }
1094         spin_unlock(&res->spinlock);
1095
1096         spin_lock(&mle->spinlock);
1097         m = mle->master;
1098         map_changed = (memcmp(mle->vote_map, mle->node_map,
1099                               sizeof(mle->vote_map)) != 0);
1100         voting_done = (memcmp(mle->vote_map, mle->response_map,
1101                              sizeof(mle->vote_map)) == 0);
1102
1103         /* restart if we hit any errors */
1104         if (map_changed) {
1105                 int b;
1106                 mlog(0, "%s: %.*s: node map changed, restarting\n",
1107                      dlm->name, res->lockname.len, res->lockname.name);
1108                 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1109                 b = (mle->type == DLM_MLE_BLOCK);
1110                 if ((*blocked && !b) || (!*blocked && b)) {
1111                         mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1112                              dlm->name, res->lockname.len, res->lockname.name,
1113                              *blocked, b);
1114                         *blocked = b;
1115                 }
1116                 spin_unlock(&mle->spinlock);
1117                 if (ret < 0) {
1118                         mlog_errno(ret);
1119                         goto leave;
1120                 }
1121                 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1122                      "rechecking now\n", dlm->name, res->lockname.len,
1123                      res->lockname.name);
1124                 goto recheck;
1125         } else {
1126                 if (!voting_done) {
1127                         mlog(0, "map not changed and voting not done "
1128                              "for %s:%.*s\n", dlm->name, res->lockname.len,
1129                              res->lockname.name);
1130                 }
1131         }
1132
1133         if (m != O2NM_MAX_NODES) {
1134                 /* another node has done an assert!
1135                  * all done! */
1136                 sleep = 0;
1137         } else {
1138                 sleep = 1;
1139                 /* have all nodes responded? */
1140                 if (voting_done && !*blocked) {
1141                         bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1142                         if (dlm->node_num <= bit) {
1143                                 /* my node number is lowest.
1144                                  * now tell other nodes that I am
1145                                  * mastering this. */
1146                                 mle->master = dlm->node_num;
1147                                 /* ref was grabbed in get_lock_resource
1148                                  * will be dropped in dlmlock_master */
1149                                 assert = 1;
1150                                 sleep = 0;
1151                         }
1152                         /* if voting is done, but we have not received
1153                          * an assert master yet, we must sleep */
1154                 }
1155         }
1156
1157         spin_unlock(&mle->spinlock);
1158
1159         /* sleep if we haven't finished voting yet */
1160         if (sleep) {
1161                 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1162
1163                 /*
1164                 if (atomic_read(&mle->mle_refs.refcount) < 2)
1165                         mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1166                         atomic_read(&mle->mle_refs.refcount),
1167                         res->lockname.len, res->lockname.name);
1168                 */
1169                 atomic_set(&mle->woken, 0);
1170                 (void)wait_event_timeout(mle->wq,
1171                                          (atomic_read(&mle->woken) == 1),
1172                                          timeo);
1173                 if (res->owner == O2NM_MAX_NODES) {
1174                         mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1175                              res->lockname.len, res->lockname.name);
1176                         goto recheck;
1177                 }
1178                 mlog(0, "done waiting, master is %u\n", res->owner);
1179                 ret = 0;
1180                 goto leave;
1181         }
1182
1183         ret = 0;   /* done */
1184         if (assert) {
1185                 m = dlm->node_num;
1186                 mlog(0, "about to master %.*s here, this=%u\n",
1187                      res->lockname.len, res->lockname.name, m);
1188                 ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
1189                 if (ret) {
1190                         /* This is a failure in the network path,
1191                          * not in the response to the assert_master
1192                          * (any nonzero response is a BUG on this node).
1193                          * Most likely a socket just got disconnected
1194                          * due to node death. */
1195                         mlog_errno(ret);
1196                 }
1197                 /* no longer need to restart lock mastery.
1198                  * all living nodes have been contacted. */
1199                 ret = 0;
1200         }
1201
1202         /* set the lockres owner */
1203         spin_lock(&res->spinlock);
1204         /* mastery reference obtained either during
1205          * assert_master_handler or in get_lock_resource */
1206         dlm_change_lockres_owner(dlm, res, m);
1207         spin_unlock(&res->spinlock);
1208
1209 leave:
1210         return ret;
1211 }
1212
1213 struct dlm_bitmap_diff_iter
1214 {
1215         int curnode;
1216         unsigned long *orig_bm;
1217         unsigned long *cur_bm;
1218         unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1219 };
1220
1221 enum dlm_node_state_change
1222 {
1223         NODE_DOWN = -1,
1224         NODE_NO_CHANGE = 0,
1225         NODE_UP
1226 };
1227
1228 static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1229                                       unsigned long *orig_bm,
1230                                       unsigned long *cur_bm)
1231 {
1232         unsigned long p1, p2;
1233         int i;
1234
1235         iter->curnode = -1;
1236         iter->orig_bm = orig_bm;
1237         iter->cur_bm = cur_bm;
1238
1239         for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1240                 p1 = *(iter->orig_bm + i);
1241                 p2 = *(iter->cur_bm + i);
1242                 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1243         }
1244 }
1245
1246 static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1247                                      enum dlm_node_state_change *state)
1248 {
1249         int bit;
1250
1251         if (iter->curnode >= O2NM_MAX_NODES)
1252                 return -ENOENT;
1253
1254         bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1255                             iter->curnode+1);
1256         if (bit >= O2NM_MAX_NODES) {
1257                 iter->curnode = O2NM_MAX_NODES;
1258                 return -ENOENT;
1259         }
1260
1261         /* if it was there in the original then this node died */
1262         if (test_bit(bit, iter->orig_bm))
1263                 *state = NODE_DOWN;
1264         else
1265                 *state = NODE_UP;
1266
1267         iter->curnode = bit;
1268         return bit;
1269 }
1270
1271
1272 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1273                                     struct dlm_lock_resource *res,
1274                                     struct dlm_master_list_entry *mle,
1275                                     int blocked)
1276 {
1277         struct dlm_bitmap_diff_iter bdi;
1278         enum dlm_node_state_change sc;
1279         int node;
1280         int ret = 0;
1281
1282         mlog(0, "something happened such that the "
1283              "master process may need to be restarted!\n");
1284
1285         assert_spin_locked(&mle->spinlock);
1286
1287         dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1288         node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1289         while (node >= 0) {
1290                 if (sc == NODE_UP) {
1291                         /* a node came up.  clear any old vote from
1292                          * the response map and set it in the vote map
1293                          * then restart the mastery. */
1294                         mlog(ML_NOTICE, "node %d up while restarting\n", node);
1295
1296                         /* redo the master request, but only for the new node */
1297                         mlog(0, "sending request to new node\n");
1298                         clear_bit(node, mle->response_map);
1299                         set_bit(node, mle->vote_map);
1300                 } else {
1301                         mlog(ML_ERROR, "node down! %d\n", node);
1302                         if (blocked) {
1303                                 int lowest = find_next_bit(mle->maybe_map,
1304                                                        O2NM_MAX_NODES, 0);
1305
1306                                 /* act like it was never there */
1307                                 clear_bit(node, mle->maybe_map);
1308
1309                                 if (node == lowest) {
1310                                         mlog(0, "expected master %u died"
1311                                             " while this node was blocked "
1312                                             "waiting on it!\n", node);
1313                                         lowest = find_next_bit(mle->maybe_map,
1314                                                         O2NM_MAX_NODES,
1315                                                         lowest+1);
1316                                         if (lowest < O2NM_MAX_NODES) {
1317                                                 mlog(0, "%s:%.*s:still "
1318                                                      "blocked. waiting on %u "
1319                                                      "now\n", dlm->name,
1320                                                      res->lockname.len,
1321                                                      res->lockname.name,
1322                                                      lowest);
1323                                         } else {
1324                                                 /* mle is an MLE_BLOCK, but
1325                                                  * there is now nothing left to
1326                                                  * block on.  we need to return
1327                                                  * all the way back out and try
1328                                                  * again with an MLE_MASTER.
1329                                                  * dlm_do_local_recovery_cleanup
1330                                                  * has already run, so the mle
1331                                                  * refcount is ok */
1332                                                 mlog(0, "%s:%.*s: no "
1333                                                      "longer blocking. try to "
1334                                                      "master this here\n",
1335                                                      dlm->name,
1336                                                      res->lockname.len,
1337                                                      res->lockname.name);
1338                                                 mle->type = DLM_MLE_MASTER;
1339                                                 mle->u.res = res;
1340                                         }
1341                                 }
1342                         }
1343
1344                         /* now blank out everything, as if we had never
1345                          * contacted anyone */
1346                         memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1347                         memset(mle->response_map, 0, sizeof(mle->response_map));
1348                         /* reset the vote_map to the current node_map */
1349                         memcpy(mle->vote_map, mle->node_map,
1350                                sizeof(mle->node_map));
1351                         /* put myself into the maybe map */
1352                         if (mle->type != DLM_MLE_BLOCK)
1353                                 set_bit(dlm->node_num, mle->maybe_map);
1354                 }
1355                 ret = -EAGAIN;
1356                 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1357         }
1358         return ret;
1359 }
1360
1361
1362 /*
1363  * DLM_MASTER_REQUEST_MSG
1364  *
1365  * returns: 0 on success,
1366  *          -errno on a network error
1367  *
1368  * on error, the caller should assume the target node is "dead"
1369  *
1370  */
1371
1372 static int dlm_do_master_request(struct dlm_lock_resource *res,
1373                                  struct dlm_master_list_entry *mle, int to)
1374 {
1375         struct dlm_ctxt *dlm = mle->dlm;
1376         struct dlm_master_request request;
1377         int ret, response=0, resend;
1378
1379         memset(&request, 0, sizeof(request));
1380         request.node_idx = dlm->node_num;
1381
1382         BUG_ON(mle->type == DLM_MLE_MIGRATION);
1383
1384         if (mle->type != DLM_MLE_MASTER) {
1385                 request.namelen = mle->u.name.len;
1386                 memcpy(request.name, mle->u.name.name, request.namelen);
1387         } else {
1388                 request.namelen = mle->u.res->lockname.len;
1389                 memcpy(request.name, mle->u.res->lockname.name,
1390                         request.namelen);
1391         }
1392
1393 again:
1394         ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1395                                  sizeof(request), to, &response);
1396         if (ret < 0)  {
1397                 if (ret == -ESRCH) {
1398                         /* should never happen */
1399                         mlog(ML_ERROR, "TCP stack not ready!\n");
1400                         BUG();
1401                 } else if (ret == -EINVAL) {
1402                         mlog(ML_ERROR, "bad args passed to o2net!\n");
1403                         BUG();
1404                 } else if (ret == -ENOMEM) {
1405                         mlog(ML_ERROR, "out of memory while trying to send "
1406                              "network message!  retrying\n");
1407                         /* this is totally crude */
1408                         msleep(50);
1409                         goto again;
1410                 } else if (!dlm_is_host_down(ret)) {
1411                         /* not a network error. bad. */
1412                         mlog_errno(ret);
1413                         mlog(ML_ERROR, "unhandled error!");
1414                         BUG();
1415                 }
1416                 /* all other errors should be network errors,
1417                  * and likely indicate node death */
1418                 mlog(ML_ERROR, "link to %d went down!\n", to);
1419                 goto out;
1420         }
1421
1422         ret = 0;
1423         resend = 0;
1424         spin_lock(&mle->spinlock);
1425         switch (response) {
1426                 case DLM_MASTER_RESP_YES:
1427                         set_bit(to, mle->response_map);
1428                         mlog(0, "node %u is the master, response=YES\n", to);
1429                         mlog(0, "%s:%.*s: master node %u now knows I have a "
1430                              "reference\n", dlm->name, res->lockname.len,
1431                              res->lockname.name, to);
1432                         mle->master = to;
1433                         break;
1434                 case DLM_MASTER_RESP_NO:
1435                         mlog(0, "node %u not master, response=NO\n", to);
1436                         set_bit(to, mle->response_map);
1437                         break;
1438                 case DLM_MASTER_RESP_MAYBE:
1439                         mlog(0, "node %u not master, response=MAYBE\n", to);
1440                         set_bit(to, mle->response_map);
1441                         set_bit(to, mle->maybe_map);
1442                         break;
1443                 case DLM_MASTER_RESP_ERROR:
1444                         mlog(0, "node %u hit an error, resending\n", to);
1445                         resend = 1;
1446                         response = 0;
1447                         break;
1448                 default:
1449                         mlog(ML_ERROR, "bad response! %u\n", response);
1450                         BUG();
1451         }
1452         spin_unlock(&mle->spinlock);
1453         if (resend) {
1454                 /* this is also totally crude */
1455                 msleep(50);
1456                 goto again;
1457         }
1458
1459 out:
1460         return ret;
1461 }
1462
1463 /*
1464  * locks that can be taken here:
1465  * dlm->spinlock
1466  * res->spinlock
1467  * mle->spinlock
1468  * dlm->master_list
1469  *
1470  * if possible, TRIM THIS DOWN!!!
1471  */
1472 int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1473                                void **ret_data)
1474 {
1475         u8 response = DLM_MASTER_RESP_MAYBE;
1476         struct dlm_ctxt *dlm = data;
1477         struct dlm_lock_resource *res = NULL;
1478         struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1479         struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1480         char *name;
1481         unsigned int namelen, hash;
1482         int found, ret;
1483         int set_maybe;
1484         int dispatch_assert = 0;
1485
1486         if (!dlm_grab(dlm))
1487                 return DLM_MASTER_RESP_NO;
1488
1489         if (!dlm_domain_fully_joined(dlm)) {
1490                 response = DLM_MASTER_RESP_NO;
1491                 goto send_response;
1492         }
1493
1494         name = request->name;
1495         namelen = request->namelen;
1496         hash = dlm_lockid_hash(name, namelen);
1497
1498         if (namelen > DLM_LOCKID_NAME_MAX) {
1499                 response = DLM_IVBUFLEN;
1500                 goto send_response;
1501         }
1502
1503 way_up_top:
1504         spin_lock(&dlm->spinlock);
1505         res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1506         if (res) {
1507                 spin_unlock(&dlm->spinlock);
1508
1509                 /* take care of the easy cases up front */
1510                 spin_lock(&res->spinlock);
1511                 if (res->state & (DLM_LOCK_RES_RECOVERING|
1512                                   DLM_LOCK_RES_MIGRATING)) {
1513                         spin_unlock(&res->spinlock);
1514                         mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1515                              "being recovered/migrated\n");
1516                         response = DLM_MASTER_RESP_ERROR;
1517                         if (mle)
1518                                 kmem_cache_free(dlm_mle_cache, mle);
1519                         goto send_response;
1520                 }
1521
1522                 if (res->owner == dlm->node_num) {
1523                         mlog(0, "%s:%.*s: setting bit %u in refmap\n",
1524                              dlm->name, namelen, name, request->node_idx);
1525                         dlm_lockres_set_refmap_bit(request->node_idx, res);
1526                         spin_unlock(&res->spinlock);
1527                         response = DLM_MASTER_RESP_YES;
1528                         if (mle)
1529                                 kmem_cache_free(dlm_mle_cache, mle);
1530
1531                         /* this node is the owner.
1532                          * there is some extra work that needs to
1533                          * happen now.  the requesting node has
1534                          * caused all nodes up to this one to
1535                          * create mles.  this node now needs to
1536                          * go back and clean those up. */
1537                         dispatch_assert = 1;
1538                         goto send_response;
1539                 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1540                         spin_unlock(&res->spinlock);
1541                         // mlog(0, "node %u is the master\n", res->owner);
1542                         response = DLM_MASTER_RESP_NO;
1543                         if (mle)
1544                                 kmem_cache_free(dlm_mle_cache, mle);
1545                         goto send_response;
1546                 }
1547
1548                 /* ok, there is no owner.  either this node is
1549                  * being blocked, or it is actively trying to
1550                  * master this lock. */
1551                 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1552                         mlog(ML_ERROR, "lock with no owner should be "
1553                              "in-progress!\n");
1554                         BUG();
1555                 }
1556
1557                 // mlog(0, "lockres is in progress...\n");
1558                 spin_lock(&dlm->master_lock);
1559                 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1560                 if (!found) {
1561                         mlog(ML_ERROR, "no mle found for this lock!\n");
1562                         BUG();
1563                 }
1564                 set_maybe = 1;
1565                 spin_lock(&tmpmle->spinlock);
1566                 if (tmpmle->type == DLM_MLE_BLOCK) {
1567                         // mlog(0, "this node is waiting for "
1568                         // "lockres to be mastered\n");
1569                         response = DLM_MASTER_RESP_NO;
1570                 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1571                         mlog(0, "node %u is master, but trying to migrate to "
1572                              "node %u.\n", tmpmle->master, tmpmle->new_master);
1573                         if (tmpmle->master == dlm->node_num) {
1574                                 mlog(ML_ERROR, "no owner on lockres, but this "
1575                                      "node is trying to migrate it to %u?!\n",
1576                                      tmpmle->new_master);
1577                                 BUG();
1578                         } else {
1579                                 /* the real master can respond on its own */
1580                                 response = DLM_MASTER_RESP_NO;
1581                         }
1582                 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1583                         set_maybe = 0;
1584                         if (tmpmle->master == dlm->node_num) {
1585                                 response = DLM_MASTER_RESP_YES;
1586                                 /* this node will be the owner.
1587                                  * go back and clean the mles on any
1588                                  * other nodes */
1589                                 dispatch_assert = 1;
1590                                 dlm_lockres_set_refmap_bit(request->node_idx, res);
1591                                 mlog(0, "%s:%.*s: setting bit %u in refmap\n",
1592                                      dlm->name, namelen, name,
1593                                      request->node_idx);
1594                         } else
1595                                 response = DLM_MASTER_RESP_NO;
1596                 } else {
1597                         // mlog(0, "this node is attempting to "
1598                         // "master lockres\n");
1599                         response = DLM_MASTER_RESP_MAYBE;
1600                 }
1601                 if (set_maybe)
1602                         set_bit(request->node_idx, tmpmle->maybe_map);
1603                 spin_unlock(&tmpmle->spinlock);
1604
1605                 spin_unlock(&dlm->master_lock);
1606                 spin_unlock(&res->spinlock);
1607
1608                 /* keep the mle attached to heartbeat events */
1609                 dlm_put_mle(tmpmle);
1610                 if (mle)
1611                         kmem_cache_free(dlm_mle_cache, mle);
1612                 goto send_response;
1613         }
1614
1615         /*
1616          * lockres doesn't exist on this node
1617          * if there is an MLE_BLOCK, return NO
1618          * if there is an MLE_MASTER, return MAYBE
1619          * otherwise, add an MLE_BLOCK, return NO
1620          */
1621         spin_lock(&dlm->master_lock);
1622         found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1623         if (!found) {
1624                 /* this lockid has never been seen on this node yet */
1625                 // mlog(0, "no mle found\n");
1626                 if (!mle) {
1627                         spin_unlock(&dlm->master_lock);
1628                         spin_unlock(&dlm->spinlock);
1629
1630                         mle = (struct dlm_master_list_entry *)
1631                                 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
1632                         if (!mle) {
1633                                 response = DLM_MASTER_RESP_ERROR;
1634                                 mlog_errno(-ENOMEM);
1635                                 goto send_response;
1636                         }
1637                         goto way_up_top;
1638                 }
1639
1640                 // mlog(0, "this is second time thru, already allocated, "
1641                 // "add the block.\n");
1642                 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1643                 set_bit(request->node_idx, mle->maybe_map);
1644                 list_add(&mle->list, &dlm->master_list);
1645                 response = DLM_MASTER_RESP_NO;
1646         } else {
1647                 // mlog(0, "mle was found\n");
1648                 set_maybe = 1;
1649                 spin_lock(&tmpmle->spinlock);
1650                 if (tmpmle->master == dlm->node_num) {
1651                         mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1652                         BUG();
1653                 }
1654                 if (tmpmle->type == DLM_MLE_BLOCK)
1655                         response = DLM_MASTER_RESP_NO;
1656                 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1657                         mlog(0, "migration mle was found (%u->%u)\n",
1658                              tmpmle->master, tmpmle->new_master);
1659                         /* real master can respond on its own */
1660                         response = DLM_MASTER_RESP_NO;
1661                 } else
1662                         response = DLM_MASTER_RESP_MAYBE;
1663                 if (set_maybe)
1664                         set_bit(request->node_idx, tmpmle->maybe_map);
1665                 spin_unlock(&tmpmle->spinlock);
1666         }
1667         spin_unlock(&dlm->master_lock);
1668         spin_unlock(&dlm->spinlock);
1669
1670         if (found) {
1671                 /* keep the mle attached to heartbeat events */
1672                 dlm_put_mle(tmpmle);
1673         }
1674 send_response:
1675
1676         if (dispatch_assert) {
1677                 if (response != DLM_MASTER_RESP_YES)
1678                         mlog(ML_ERROR, "invalid response %d\n", response);
1679                 if (!res) {
1680                         mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1681                         BUG();
1682                 }
1683                 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1684                              dlm->node_num, res->lockname.len, res->lockname.name);
1685                 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1686                                                  DLM_ASSERT_MASTER_MLE_CLEANUP);
1687                 if (ret < 0) {
1688                         mlog(ML_ERROR, "failed to dispatch assert master work\n");
1689                         response = DLM_MASTER_RESP_ERROR;
1690                 }
1691         }
1692
1693         dlm_put(dlm);
1694         return response;
1695 }
1696
1697 /*
1698  * DLM_ASSERT_MASTER_MSG
1699  */
1700
1701
1702 /*
1703  * NOTE: this can be used for debugging
1704  * can periodically run all locks owned by this node
1705  * and re-assert across the cluster...
1706  */
1707 int dlm_do_assert_master(struct dlm_ctxt *dlm,
1708                          struct dlm_lock_resource *res,
1709                          void *nodemap, u32 flags)
1710 {
1711         struct dlm_assert_master assert;
1712         int to, tmpret;
1713         struct dlm_node_iter iter;
1714         int ret = 0;
1715         int reassert;
1716         const char *lockname = res->lockname.name;
1717         unsigned int namelen = res->lockname.len;
1718
1719         BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1720 again:
1721         reassert = 0;
1722
1723         /* note that if this nodemap is empty, it returns 0 */
1724         dlm_node_iter_init(nodemap, &iter);
1725         while ((to = dlm_node_iter_next(&iter)) >= 0) {
1726                 int r = 0;
1727                 struct dlm_master_list_entry *mle = NULL;
1728
1729                 mlog(0, "sending assert master to %d (%.*s)\n", to,
1730                      namelen, lockname);
1731                 memset(&assert, 0, sizeof(assert));
1732                 assert.node_idx = dlm->node_num;
1733                 assert.namelen = namelen;
1734                 memcpy(assert.name, lockname, namelen);
1735                 assert.flags = cpu_to_be32(flags);
1736
1737                 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1738                                             &assert, sizeof(assert), to, &r);
1739                 if (tmpret < 0) {
1740                         mlog(0, "assert_master returned %d!\n", tmpret);
1741                         if (!dlm_is_host_down(tmpret)) {
1742                                 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1743                                 BUG();
1744                         }
1745                         /* a node died.  finish out the rest of the nodes. */
1746                         mlog(0, "link to %d went down!\n", to);
1747                         /* any nonzero status return will do */
1748                         ret = tmpret;
1749                         r = 0;
1750                 } else if (r < 0) {
1751                         /* ok, something horribly messed.  kill thyself. */
1752                         mlog(ML_ERROR,"during assert master of %.*s to %u, "
1753                              "got %d.\n", namelen, lockname, to, r);
1754                         spin_lock(&dlm->spinlock);
1755                         spin_lock(&dlm->master_lock);
1756                         if (dlm_find_mle(dlm, &mle, (char *)lockname,
1757                                          namelen)) {
1758                                 dlm_print_one_mle(mle);
1759                                 __dlm_put_mle(mle);
1760                         }
1761                         spin_unlock(&dlm->master_lock);
1762                         spin_unlock(&dlm->spinlock);
1763                         BUG();
1764                 }
1765
1766                 if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1767                     !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1768                                 mlog(ML_ERROR, "%.*s: very strange, "
1769                                      "master MLE but no lockres on %u\n",
1770                                      namelen, lockname, to);
1771                 }
1772
1773                 if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1774                         mlog(0, "%.*s: node %u create mles on other "
1775                              "nodes and requests a re-assert\n",
1776                              namelen, lockname, to);
1777                         reassert = 1;
1778                 }
1779                 if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1780                         mlog(0, "%.*s: node %u has a reference to this "
1781                              "lockres, set the bit in the refmap\n",
1782                              namelen, lockname, to);
1783                         spin_lock(&res->spinlock);
1784                         dlm_lockres_set_refmap_bit(to, res);
1785                         spin_unlock(&res->spinlock);
1786                 }
1787         }
1788
1789         if (reassert)
1790                 goto again;
1791
1792         return ret;
1793 }
1794
1795 /*
1796  * locks that can be taken here:
1797  * dlm->spinlock
1798  * res->spinlock
1799  * mle->spinlock
1800  * dlm->master_list
1801  *
1802  * if possible, TRIM THIS DOWN!!!
1803  */
1804 int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1805                               void **ret_data)
1806 {
1807         struct dlm_ctxt *dlm = data;
1808         struct dlm_master_list_entry *mle = NULL;
1809         struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1810         struct dlm_lock_resource *res = NULL;
1811         char *name;
1812         unsigned int namelen, hash;
1813         u32 flags;
1814         int master_request = 0, have_lockres_ref = 0;
1815         int ret = 0;
1816
1817         if (!dlm_grab(dlm))
1818                 return 0;
1819
1820         name = assert->name;
1821         namelen = assert->namelen;
1822         hash = dlm_lockid_hash(name, namelen);
1823         flags = be32_to_cpu(assert->flags);
1824
1825         if (namelen > DLM_LOCKID_NAME_MAX) {
1826                 mlog(ML_ERROR, "Invalid name length!");
1827                 goto done;
1828         }
1829
1830         spin_lock(&dlm->spinlock);
1831
1832         if (flags)
1833                 mlog(0, "assert_master with flags: %u\n", flags);
1834
1835         /* find the MLE */
1836         spin_lock(&dlm->master_lock);
1837         if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1838                 /* not an error, could be master just re-asserting */
1839                 mlog(0, "just got an assert_master from %u, but no "
1840                      "MLE for it! (%.*s)\n", assert->node_idx,
1841                      namelen, name);
1842         } else {
1843                 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1844                 if (bit >= O2NM_MAX_NODES) {
1845                         /* not necessarily an error, though less likely.
1846                          * could be master just re-asserting. */
1847                         mlog(0, "no bits set in the maybe_map, but %u "
1848                              "is asserting! (%.*s)\n", assert->node_idx,
1849                              namelen, name);
1850                 } else if (bit != assert->node_idx) {
1851                         if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1852                                 mlog(0, "master %u was found, %u should "
1853                                      "back off\n", assert->node_idx, bit);
1854                         } else {
1855                                 /* with the fix for bug 569, a higher node
1856                                  * number winning the mastery will respond
1857                                  * YES to mastery requests, but this node
1858                                  * had no way of knowing.  let it pass. */
1859                                 mlog(0, "%u is the lowest node, "
1860                                      "%u is asserting. (%.*s)  %u must "
1861                                      "have begun after %u won.\n", bit,
1862                                      assert->node_idx, namelen, name, bit,
1863                                      assert->node_idx);
1864                         }
1865                 }
1866                 if (mle->type == DLM_MLE_MIGRATION) {
1867                         if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1868                                 mlog(0, "%s:%.*s: got cleanup assert"
1869                                      " from %u for migration\n",
1870                                      dlm->name, namelen, name,
1871                                      assert->node_idx);
1872                         } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1873                                 mlog(0, "%s:%.*s: got unrelated assert"
1874                                      " from %u for migration, ignoring\n",
1875                                      dlm->name, namelen, name,
1876                                      assert->node_idx);
1877                                 __dlm_put_mle(mle);
1878                                 spin_unlock(&dlm->master_lock);
1879                                 spin_unlock(&dlm->spinlock);
1880                                 goto done;
1881                         }
1882                 }
1883         }
1884         spin_unlock(&dlm->master_lock);
1885
1886         /* ok everything checks out with the MLE
1887          * now check to see if there is a lockres */
1888         res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1889         if (res) {
1890                 spin_lock(&res->spinlock);
1891                 if (res->state & DLM_LOCK_RES_RECOVERING)  {
1892                         mlog(ML_ERROR, "%u asserting but %.*s is "
1893                              "RECOVERING!\n", assert->node_idx, namelen, name);
1894                         goto kill;
1895                 }
1896                 if (!mle) {
1897                         if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1898                             res->owner != assert->node_idx) {
1899                                 mlog(ML_ERROR, "assert_master from "
1900                                           "%u, but current owner is "
1901                                           "%u! (%.*s)\n",
1902                                        assert->node_idx, res->owner,
1903                                        namelen, name);
1904                                 goto kill;
1905                         }
1906                 } else if (mle->type != DLM_MLE_MIGRATION) {
1907                         if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1908                                 /* owner is just re-asserting */
1909                                 if (res->owner == assert->node_idx) {
1910                                         mlog(0, "owner %u re-asserting on "
1911                                              "lock %.*s\n", assert->node_idx,
1912                                              namelen, name);
1913                                         goto ok;
1914                                 }
1915                                 mlog(ML_ERROR, "got assert_master from "
1916                                      "node %u, but %u is the owner! "
1917                                      "(%.*s)\n", assert->node_idx,
1918                                      res->owner, namelen, name);
1919                                 goto kill;
1920                         }
1921                         if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1922                                 mlog(ML_ERROR, "got assert from %u, but lock "
1923                                      "with no owner should be "
1924                                      "in-progress! (%.*s)\n",
1925                                      assert->node_idx,
1926                                      namelen, name);
1927                                 goto kill;
1928                         }
1929                 } else /* mle->type == DLM_MLE_MIGRATION */ {
1930                         /* should only be getting an assert from new master */
1931                         if (assert->node_idx != mle->new_master) {
1932                                 mlog(ML_ERROR, "got assert from %u, but "
1933                                      "new master is %u, and old master "
1934                                      "was %u (%.*s)\n",
1935                                      assert->node_idx, mle->new_master,
1936                                      mle->master, namelen, name);
1937                                 goto kill;
1938                         }
1939
1940                 }
1941 ok:
1942                 spin_unlock(&res->spinlock);
1943         }
1944         spin_unlock(&dlm->spinlock);
1945
1946         // mlog(0, "woo!  got an assert_master from node %u!\n",
1947         //           assert->node_idx);
1948         if (mle) {
1949                 int extra_ref = 0;
1950                 int nn = -1;
1951                 int rr, err = 0;
1952
1953                 spin_lock(&mle->spinlock);
1954                 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1955                         extra_ref = 1;
1956                 else {
1957                         /* MASTER mle: if any bits set in the response map
1958                          * then the calling node needs to re-assert to clear
1959                          * up nodes that this node contacted */
1960                         while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1961                                                     nn+1)) < O2NM_MAX_NODES) {
1962                                 if (nn != dlm->node_num && nn != assert->node_idx)
1963                                         master_request = 1;
1964                         }
1965                 }
1966                 mle->master = assert->node_idx;
1967                 atomic_set(&mle->woken, 1);
1968                 wake_up(&mle->wq);
1969                 spin_unlock(&mle->spinlock);
1970
1971                 if (res) {
1972                         int wake = 0;
1973                         spin_lock(&res->spinlock);
1974                         if (mle->type == DLM_MLE_MIGRATION) {
1975                                 mlog(0, "finishing off migration of lockres %.*s, "
1976                                         "from %u to %u\n",
1977                                         res->lockname.len, res->lockname.name,
1978                                         dlm->node_num, mle->new_master);
1979                                 res->state &= ~DLM_LOCK_RES_MIGRATING;
1980                                 wake = 1;
1981                                 dlm_change_lockres_owner(dlm, res, mle->new_master);
1982                                 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1983                         } else {
1984                                 dlm_change_lockres_owner(dlm, res, mle->master);
1985                         }
1986                         spin_unlock(&res->spinlock);
1987                         have_lockres_ref = 1;
1988                         if (wake)
1989                                 wake_up(&res->wq);
1990                 }
1991
1992                 /* master is known, detach if not already detached.
1993                  * ensures that only one assert_master call will happen
1994                  * on this mle. */
1995                 spin_lock(&dlm->spinlock);
1996                 spin_lock(&dlm->master_lock);
1997
1998                 rr = atomic_read(&mle->mle_refs.refcount);
1999                 if (mle->inuse > 0) {
2000                         if (extra_ref && rr < 3)
2001                                 err = 1;
2002                         else if (!extra_ref && rr < 2)
2003                                 err = 1;
2004                 } else {
2005                         if (extra_ref && rr < 2)
2006                                 err = 1;
2007                         else if (!extra_ref && rr < 1)
2008                                 err = 1;
2009                 }
2010                 if (err) {
2011                         mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
2012                              "that will mess up this node, refs=%d, extra=%d, "
2013                              "inuse=%d\n", dlm->name, namelen, name,
2014                              assert->node_idx, rr, extra_ref, mle->inuse);
2015                         dlm_print_one_mle(mle);
2016                 }
2017                 list_del_init(&mle->list);
2018                 __dlm_mle_detach_hb_events(dlm, mle);
2019                 __dlm_put_mle(mle);
2020                 if (extra_ref) {
2021                         /* the assert master message now balances the extra
2022                          * ref given by the master / migration request message.
2023                          * if this is the last put, it will be removed
2024                          * from the list. */
2025                         __dlm_put_mle(mle);
2026                 }
2027                 spin_unlock(&dlm->master_lock);
2028                 spin_unlock(&dlm->spinlock);
2029         } else if (res) {
2030                 if (res->owner != assert->node_idx) {
2031                         mlog(0, "assert_master from %u, but current "
2032                              "owner is %u (%.*s), no mle\n", assert->node_idx,
2033                              res->owner, namelen, name);
2034                 }
2035         }
2036
2037 done:
2038         ret = 0;
2039         if (res) {
2040                 spin_lock(&res->spinlock);
2041                 res->state |= DLM_LOCK_RES_SETREF_INPROG;
2042                 spin_unlock(&res->spinlock);
2043                 *ret_data = (void *)res;
2044         }
2045         dlm_put(dlm);
2046         if (master_request) {
2047                 mlog(0, "need to tell master to reassert\n");
2048                 /* positive. negative would shoot down the node. */
2049                 ret |= DLM_ASSERT_RESPONSE_REASSERT;
2050                 if (!have_lockres_ref) {
2051                         mlog(ML_ERROR, "strange, got assert from %u, MASTER "
2052                              "mle present here for %s:%.*s, but no lockres!\n",
2053                              assert->node_idx, dlm->name, namelen, name);
2054                 }
2055         }
2056         if (have_lockres_ref) {
2057                 /* let the master know we have a reference to the lockres */
2058                 ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2059                 mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2060                      dlm->name, namelen, name, assert->node_idx);
2061         }
2062         return ret;
2063
2064 kill:
2065         /* kill the caller! */
2066         mlog(ML_ERROR, "Bad message received from another node.  Dumping state "
2067              "and killing the other node now!  This node is OK and can continue.\n");
2068         __dlm_print_one_lock_resource(res);
2069         spin_unlock(&res->spinlock);
2070         spin_unlock(&dlm->spinlock);
2071         *ret_data = (void *)res;
2072         dlm_put(dlm);
2073         return -EINVAL;
2074 }
2075
2076 void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2077 {
2078         struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2079
2080         if (ret_data) {
2081                 spin_lock(&res->spinlock);
2082                 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2083                 spin_unlock(&res->spinlock);
2084                 wake_up(&res->wq);
2085                 dlm_lockres_put(res);
2086         }
2087         return;
2088 }
2089
2090 int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2091                                struct dlm_lock_resource *res,
2092                                int ignore_higher, u8 request_from, u32 flags)
2093 {
2094         struct dlm_work_item *item;
2095         item = kzalloc(sizeof(*item), GFP_NOFS);
2096         if (!item)
2097                 return -ENOMEM;
2098
2099
2100         /* queue up work for dlm_assert_master_worker */
2101         dlm_grab(dlm);  /* get an extra ref for the work item */
2102         dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2103         item->u.am.lockres = res; /* already have a ref */
2104         /* can optionally ignore node numbers higher than this node */
2105         item->u.am.ignore_higher = ignore_higher;
2106         item->u.am.request_from = request_from;
2107         item->u.am.flags = flags;
2108
2109         if (ignore_higher)
2110                 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2111                      res->lockname.name);
2112
2113         spin_lock(&dlm->work_lock);
2114         list_add_tail(&item->list, &dlm->work_list);
2115         spin_unlock(&dlm->work_lock);
2116
2117         queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2118         return 0;
2119 }
2120
2121 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2122 {
2123         struct dlm_ctxt *dlm = data;
2124         int ret = 0;
2125         struct dlm_lock_resource *res;
2126         unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2127         int ignore_higher;
2128         int bit;
2129         u8 request_from;
2130         u32 flags;
2131
2132         dlm = item->dlm;
2133         res = item->u.am.lockres;
2134         ignore_higher = item->u.am.ignore_higher;
2135         request_from = item->u.am.request_from;
2136         flags = item->u.am.flags;
2137
2138         spin_lock(&dlm->spinlock);
2139         memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2140         spin_unlock(&dlm->spinlock);
2141
2142         clear_bit(dlm->node_num, nodemap);
2143         if (ignore_higher) {
2144                 /* if is this just to clear up mles for nodes below
2145                  * this node, do not send the message to the original
2146                  * caller or any node number higher than this */
2147                 clear_bit(request_from, nodemap);
2148                 bit = dlm->node_num;
2149                 while (1) {
2150                         bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2151                                             bit+1);
2152                         if (bit >= O2NM_MAX_NODES)
2153                                 break;
2154                         clear_bit(bit, nodemap);
2155                 }
2156         }
2157
2158         /*
2159          * If we're migrating this lock to someone else, we are no
2160          * longer allowed to assert out own mastery.  OTOH, we need to
2161          * prevent migration from starting while we're still asserting
2162          * our dominance.  The reserved ast delays migration.
2163          */
2164         spin_lock(&res->spinlock);
2165         if (res->state & DLM_LOCK_RES_MIGRATING) {
2166                 mlog(0, "Someone asked us to assert mastery, but we're "
2167                      "in the middle of migration.  Skipping assert, "
2168                      "the new master will handle that.\n");
2169                 spin_unlock(&res->spinlock);
2170                 goto put;
2171         } else
2172                 __dlm_lockres_reserve_ast(res);
2173         spin_unlock(&res->spinlock);
2174
2175         /* this call now finishes out the nodemap
2176          * even if one or more nodes die */
2177         mlog(0, "worker about to master %.*s here, this=%u\n",
2178                      res->lockname.len, res->lockname.name, dlm->node_num);
2179         ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2180         if (ret < 0) {
2181                 /* no need to restart, we are done */
2182                 if (!dlm_is_host_down(ret))
2183                         mlog_errno(ret);
2184         }
2185
2186         /* Ok, we've asserted ourselves.  Let's let migration start. */
2187         dlm_lockres_release_ast(dlm, res);
2188
2189 put:
2190         dlm_lockres_put(res);
2191
2192         mlog(0, "finished with dlm_assert_master_worker\n");
2193 }
2194
2195 /* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2196  * We cannot wait for node recovery to complete to begin mastering this
2197  * lockres because this lockres is used to kick off recovery! ;-)
2198  * So, do a pre-check on all living nodes to see if any of those nodes
2199  * think that $RECOVERY is currently mastered by a dead node.  If so,
2200  * we wait a short time to allow that node to get notified by its own
2201  * heartbeat stack, then check again.  All $RECOVERY lock resources
2202  * mastered by dead nodes are purged when the hearbeat callback is
2203  * fired, so we can know for sure that it is safe to continue once
2204  * the node returns a live node or no node.  */
2205 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2206                                        struct dlm_lock_resource *res)
2207 {
2208         struct dlm_node_iter iter;
2209         int nodenum;
2210         int ret = 0;
2211         u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2212
2213         spin_lock(&dlm->spinlock);
2214         dlm_node_iter_init(dlm->domain_map, &iter);
2215         spin_unlock(&dlm->spinlock);
2216
2217         while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2218                 /* do not send to self */
2219                 if (nodenum == dlm->node_num)
2220                         continue;
2221                 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2222                 if (ret < 0) {
2223                         mlog_errno(ret);
2224                         if (!dlm_is_host_down(ret))
2225                                 BUG();
2226                         /* host is down, so answer for that node would be
2227                          * DLM_LOCK_RES_OWNER_UNKNOWN.  continue. */
2228                         ret = 0;
2229                 }
2230
2231                 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2232                         /* check to see if this master is in the recovery map */
2233                         spin_lock(&dlm->spinlock);
2234                         if (test_bit(master, dlm->recovery_map)) {
2235                                 mlog(ML_NOTICE, "%s: node %u has not seen "
2236                                      "node %u go down yet, and thinks the "
2237                                      "dead node is mastering the recovery "
2238                                      "lock.  must wait.\n", dlm->name,
2239                                      nodenum, master);
2240                                 ret = -EAGAIN;
2241                         }
2242                         spin_unlock(&dlm->spinlock);
2243                         mlog(0, "%s: reco lock master is %u\n", dlm->name,
2244                              master);
2245                         break;
2246                 }
2247         }
2248         return ret;
2249 }
2250
2251 /*
2252  * DLM_DEREF_LOCKRES_MSG
2253  */
2254
2255 int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2256 {
2257         struct dlm_deref_lockres deref;
2258         int ret = 0, r;
2259         const char *lockname;
2260         unsigned int namelen;
2261
2262         lockname = res->lockname.name;
2263         namelen = res->lockname.len;
2264         BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2265
2266         mlog(0, "%s:%.*s: sending deref to %d\n",
2267              dlm->name, namelen, lockname, res->owner);
2268         memset(&deref, 0, sizeof(deref));
2269         deref.node_idx = dlm->node_num;
2270         deref.namelen = namelen;
2271         memcpy(deref.name, lockname, namelen);
2272
2273         ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2274                                  &deref, sizeof(deref), res->owner, &r);
2275         if (ret < 0)
2276                 mlog_errno(ret);
2277         else if (r < 0) {
2278                 /* BAD.  other node says I did not have a ref. */
2279                 mlog(ML_ERROR,"while dropping ref on %s:%.*s "
2280                     "(master=%u) got %d.\n", dlm->name, namelen,
2281                     lockname, res->owner, r);
2282                 dlm_print_one_lock_resource(res);
2283                 BUG();
2284         }
2285         return ret;
2286 }
2287
2288 int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2289                               void **ret_data)
2290 {
2291         struct dlm_ctxt *dlm = data;
2292         struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2293         struct dlm_lock_resource *res = NULL;
2294         char *name;
2295         unsigned int namelen;
2296         int ret = -EINVAL;
2297         u8 node;
2298         unsigned int hash;
2299
2300         if (!dlm_grab(dlm))
2301                 return 0;
2302
2303         name = deref->name;
2304         namelen = deref->namelen;
2305         node = deref->node_idx;
2306
2307         if (namelen > DLM_LOCKID_NAME_MAX) {
2308                 mlog(ML_ERROR, "Invalid name length!");
2309                 goto done;
2310         }
2311         if (deref->node_idx >= O2NM_MAX_NODES) {
2312                 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2313                 goto done;
2314         }
2315
2316         hash = dlm_lockid_hash(name, namelen);
2317
2318         spin_lock(&dlm->spinlock);
2319         res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2320         if (!res) {
2321                 spin_unlock(&dlm->spinlock);
2322                 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2323                      dlm->name, namelen, name);
2324                 goto done;
2325         }
2326         spin_unlock(&dlm->spinlock);
2327
2328         spin_lock(&res->spinlock);
2329         BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2330         if (test_bit(node, res->refmap)) {
2331                 ret = 0;
2332                 dlm_lockres_clear_refmap_bit(node, res);
2333         } else {
2334                 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2335                      "but it is already dropped!\n", dlm->name, namelen,
2336                      name, node);
2337                 __dlm_print_one_lock_resource(res);
2338         }
2339         spin_unlock(&res->spinlock);
2340
2341         if (!ret)
2342                 dlm_lockres_calc_usage(dlm, res);
2343 done:
2344         if (res)
2345                 dlm_lockres_put(res);
2346         dlm_put(dlm);
2347         return ret;
2348 }
2349
2350
2351 /*
2352  * DLM_MIGRATE_LOCKRES
2353  */
2354
2355
2356 static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2357                                struct dlm_lock_resource *res,
2358                                u8 target)
2359 {
2360         struct dlm_master_list_entry *mle = NULL;
2361         struct dlm_master_list_entry *oldmle = NULL;
2362         struct dlm_migratable_lockres *mres = NULL;
2363         int ret = -EINVAL;
2364         const char *name;
2365         unsigned int namelen;
2366         int mle_added = 0;
2367         struct list_head *queue, *iter;
2368         int i;
2369         struct dlm_lock *lock;
2370         int empty = 1, wake = 0;
2371
2372         if (!dlm_grab(dlm))
2373                 return -EINVAL;
2374
2375         name = res->lockname.name;
2376         namelen = res->lockname.len;
2377
2378         mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2379
2380         /*
2381          * ensure this lockres is a proper candidate for migration
2382          */
2383         spin_lock(&res->spinlock);
2384         if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2385                 mlog(0, "cannot migrate lockres with unknown owner!\n");
2386                 spin_unlock(&res->spinlock);
2387                 goto leave;
2388         }
2389         if (res->owner != dlm->node_num) {
2390                 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2391                 spin_unlock(&res->spinlock);
2392                 goto leave;
2393         }
2394         mlog(0, "checking queues...\n");
2395         queue = &res->granted;
2396         for (i=0; i<3; i++) {
2397                 list_for_each(iter, queue) {
2398                         lock = list_entry (iter, struct dlm_lock, list);
2399                         empty = 0;
2400                         if (lock->ml.node == dlm->node_num) {
2401                                 mlog(0, "found a lock owned by this node "
2402                                      "still on the %s queue!  will not "
2403                                      "migrate this lockres\n",
2404                                      i==0 ? "granted" :
2405                                      (i==1 ? "converting" : "blocked"));
2406                                 spin_unlock(&res->spinlock);
2407                                 ret = -ENOTEMPTY;
2408                                 goto leave;
2409                         }
2410                 }
2411                 queue++;
2412         }
2413         mlog(0, "all locks on this lockres are nonlocal.  continuing\n");
2414         spin_unlock(&res->spinlock);
2415
2416         /* no work to do */
2417         if (empty) {
2418                 mlog(0, "no locks were found on this lockres! done!\n");
2419                 ret = 0;
2420                 goto leave;
2421         }
2422
2423         /*
2424          * preallocate up front
2425          * if this fails, abort
2426          */
2427
2428         ret = -ENOMEM;
2429         mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2430         if (!mres) {
2431                 mlog_errno(ret);
2432                 goto leave;
2433         }
2434
2435         mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2436                                                                 GFP_NOFS);
2437         if (!mle) {
2438                 mlog_errno(ret);
2439                 goto leave;
2440         }
2441         ret = 0;
2442
2443         /*
2444          * find a node to migrate the lockres to
2445          */
2446
2447         mlog(0, "picking a migration node\n");
2448         spin_lock(&dlm->spinlock);
2449         /* pick a new node */
2450         if (!test_bit(target, dlm->domain_map) ||
2451             target >= O2NM_MAX_NODES) {
2452                 target = dlm_pick_migration_target(dlm, res);
2453         }
2454         mlog(0, "node %u chosen for migration\n", target);
2455
2456         if (target >= O2NM_MAX_NODES ||
2457             !test_bit(target, dlm->domain_map)) {
2458                 /* target chosen is not alive */
2459                 ret = -EINVAL;
2460         }
2461
2462         if (ret) {
2463                 spin_unlock(&dlm->spinlock);
2464                 goto fail;
2465         }
2466
2467         mlog(0, "continuing with target = %u\n", target);
2468
2469         /*
2470          * clear any existing master requests and
2471          * add the migration mle to the list
2472          */
2473         spin_lock(&dlm->master_lock);
2474         ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2475                                     namelen, target, dlm->node_num);
2476         spin_unlock(&dlm->master_lock);
2477         spin_unlock(&dlm->spinlock);
2478
2479         if (ret == -EEXIST) {
2480                 mlog(0, "another process is already migrating it\n");
2481                 goto fail;
2482         }
2483         mle_added = 1;
2484
2485         /*
2486          * set the MIGRATING flag and flush asts
2487          * if we fail after this we need to re-dirty the lockres
2488          */
2489         if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2490                 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2491                      "the target went down.\n", res->lockname.len,
2492                      res->lockname.name, target);
2493                 spin_lock(&res->spinlock);
2494                 res->state &= ~DLM_LOCK_RES_MIGRATING;
2495                 wake = 1;
2496                 spin_unlock(&res->spinlock);
2497                 ret = -EINVAL;
2498         }
2499
2500 fail:
2501         if (oldmle) {
2502                 /* master is known, detach if not already detached */
2503                 dlm_mle_detach_hb_events(dlm, oldmle);
2504                 dlm_put_mle(oldmle);
2505         }
2506
2507         if (ret < 0) {
2508                 if (mle_added) {
2509                         dlm_mle_detach_hb_events(dlm, mle);
2510                         dlm_put_mle(mle);
2511                 } else if (mle) {
2512                         kmem_cache_free(dlm_mle_cache, mle);
2513                 }
2514                 goto leave;
2515         }
2516
2517         /*
2518          * at this point, we have a migration target, an mle
2519          * in the master list, and the MIGRATING flag set on
2520          * the lockres
2521          */
2522
2523         /* now that remote nodes are spinning on the MIGRATING flag,
2524          * ensure that all assert_master work is flushed. */
2525         flush_workqueue(dlm->dlm_worker);
2526
2527         /* get an extra reference on the mle.
2528          * otherwise the assert_master from the new
2529          * master will destroy this.
2530          * also, make sure that all callers of dlm_get_mle
2531          * take both dlm->spinlock and dlm->master_lock */
2532         spin_lock(&dlm->spinlock);
2533         spin_lock(&dlm->master_lock);
2534         dlm_get_mle_inuse(mle);
2535         spin_unlock(&dlm->master_lock);
2536         spin_unlock(&dlm->spinlock);
2537
2538         /* notify new node and send all lock state */
2539         /* call send_one_lockres with migration flag.
2540          * this serves as notice to the target node that a
2541          * migration is starting. */
2542         ret = dlm_send_one_lockres(dlm, res, mres, target,
2543                                    DLM_MRES_MIGRATION);
2544
2545         if (ret < 0) {
2546                 mlog(0, "migration to node %u failed with %d\n",
2547                      target, ret);
2548                 /* migration failed, detach and clean up mle */
2549                 dlm_mle_detach_hb_events(dlm, mle);
2550                 dlm_put_mle(mle);
2551                 dlm_put_mle_inuse(mle);
2552                 spin_lock(&res->spinlock);
2553                 res->state &= ~DLM_LOCK_RES_MIGRATING;
2554                 wake = 1;
2555                 spin_unlock(&res->spinlock);
2556                 goto leave;
2557         }
2558
2559         /* at this point, the target sends a message to all nodes,
2560          * (using dlm_do_migrate_request).  this node is skipped since
2561          * we had to put an mle in the list to begin the process.  this
2562          * node now waits for target to do an assert master.  this node
2563          * will be the last one notified, ensuring that the migration
2564          * is complete everywhere.  if the target dies while this is
2565          * going on, some nodes could potentially see the target as the
2566          * master, so it is important that my recovery finds the migration
2567          * mle and sets the master to UNKNONWN. */
2568
2569
2570         /* wait for new node to assert master */
2571         while (1) {
2572                 ret = wait_event_interruptible_timeout(mle->wq,
2573                                         (atomic_read(&mle->woken) == 1),
2574                                         msecs_to_jiffies(5000));
2575
2576                 if (ret >= 0) {
2577                         if (atomic_read(&mle->woken) == 1 ||
2578                             res->owner == target)
2579                                 break;
2580
2581                         mlog(0, "%s:%.*s: timed out during migration\n",
2582                              dlm->name, res->lockname.len, res->lockname.name);
2583                         /* avoid hang during shutdown when migrating lockres
2584                          * to a node which also goes down */
2585                         if (dlm_is_node_dead(dlm, target)) {
2586                                 mlog(0, "%s:%.*s: expected migration "
2587                                      "target %u is no longer up, restarting\n",
2588                                      dlm->name, res->lockname.len,
2589                                      res->lockname.name, target);
2590                                 ret = -EINVAL;
2591                                 /* migration failed, detach and clean up mle */
2592                                 dlm_mle_detach_hb_events(dlm, mle);
2593                                 dlm_put_mle(mle);
2594                                 dlm_put_mle_inuse(mle);
2595                                 spin_lock(&res->spinlock);
2596                                 res->state &= ~DLM_LOCK_RES_MIGRATING;
2597                                 wake = 1;
2598                                 spin_unlock(&res->spinlock);
2599                                 goto leave;
2600                         }
2601                 } else
2602                         mlog(0, "%s:%.*s: caught signal during migration\n",
2603                              dlm->name, res->lockname.len, res->lockname.name);
2604         }
2605
2606         /* all done, set the owner, clear the flag */
2607         spin_lock(&res->spinlock);
2608         dlm_set_lockres_owner(dlm, res, target);
2609         res->state &= ~DLM_LOCK_RES_MIGRATING;
2610         dlm_remove_nonlocal_locks(dlm, res);
2611         spin_unlock(&res->spinlock);
2612         wake_up(&res->wq);
2613
2614         /* master is known, detach if not already detached */
2615         dlm_mle_detach_hb_events(dlm, mle);
2616         dlm_put_mle_inuse(mle);
2617         ret = 0;
2618
2619         dlm_lockres_calc_usage(dlm, res);
2620
2621 leave:
2622         /* re-dirty the lockres if we failed */
2623         if (ret < 0)
2624                 dlm_kick_thread(dlm, res);
2625
2626         /* wake up waiters if the MIGRATING flag got set
2627          * but migration failed */
2628         if (wake)
2629                 wake_up(&res->wq);
2630
2631         /* TODO: cleanup */
2632         if (mres)
2633                 free_page((unsigned long)mres);
2634
2635         dlm_put(dlm);
2636
2637         mlog(0, "returning %d\n", ret);
2638         return ret;
2639 }
2640
2641 #define DLM_MIGRATION_RETRY_MS  100
2642
2643 /* Should be called only after beginning the domain leave process.
2644  * There should not be any remaining locks on nonlocal lock resources,
2645  * and there should be no local locks left on locally mastered resources.
2646  *
2647  * Called with the dlm spinlock held, may drop it to do migration, but
2648  * will re-acquire before exit.
2649  *
2650  * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped */
2651 int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2652 {
2653         int ret;
2654         int lock_dropped = 0;
2655
2656         if (res->owner != dlm->node_num) {
2657                 if (!__dlm_lockres_unused(res)) {
2658                         mlog(ML_ERROR, "%s:%.*s: this node is not master, "
2659                              "trying to free this but locks remain\n",
2660                              dlm->name, res->lockname.len, res->lockname.name);
2661                 }
2662                 goto leave;
2663         }
2664
2665         /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2666         spin_unlock(&dlm->spinlock);
2667         lock_dropped = 1;
2668         while (1) {
2669                 ret = dlm_migrate_lockres(dlm, res, O2NM_MAX_NODES);
2670                 if (ret >= 0)
2671                         break;
2672                 if (ret == -ENOTEMPTY) {
2673                         mlog(ML_ERROR, "lockres %.*s still has local locks!\n",
2674                                 res->lockname.len, res->lockname.name);
2675                         BUG();
2676                 }
2677
2678                 mlog(0, "lockres %.*s: migrate failed, "
2679                      "retrying\n", res->lockname.len,
2680                      res->lockname.name);
2681                 msleep(DLM_MIGRATION_RETRY_MS);
2682         }
2683         spin_lock(&dlm->spinlock);
2684 leave:
2685         return lock_dropped;
2686 }
2687
2688 int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2689 {
2690         int ret;
2691         spin_lock(&dlm->ast_lock);
2692         spin_lock(&lock->spinlock);
2693         ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2694         spin_unlock(&lock->spinlock);
2695         spin_unlock(&dlm->ast_lock);
2696         return ret;
2697 }
2698
2699 static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2700                                      struct dlm_lock_resource *res,
2701                                      u8 mig_target)
2702 {
2703         int can_proceed;
2704         spin_lock(&res->spinlock);
2705         can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2706         spin_unlock(&res->spinlock);
2707
2708         /* target has died, so make the caller break out of the
2709          * wait_event, but caller must recheck the domain_map */
2710         spin_lock(&dlm->spinlock);
2711         if (!test_bit(mig_target, dlm->domain_map))
2712                 can_proceed = 1;
2713         spin_unlock(&dlm->spinlock);
2714         return can_proceed;
2715 }
2716
2717 static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2718                                 struct dlm_lock_resource *res)
2719 {
2720         int ret;
2721         spin_lock(&res->spinlock);
2722         ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2723         spin_unlock(&res->spinlock);
2724         return ret;
2725 }
2726
2727
2728 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2729                                        struct dlm_lock_resource *res,
2730                                        u8 target)
2731 {
2732         int ret = 0;
2733
2734         mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2735                res->lockname.len, res->lockname.name, dlm->node_num,
2736                target);
2737         /* need to set MIGRATING flag on lockres.  this is done by
2738          * ensuring that all asts have been flushed for this lockres. */
2739         spin_lock(&res->spinlock);
2740         BUG_ON(res->migration_pending);
2741         res->migration_pending = 1;
2742         /* strategy is to reserve an extra ast then release
2743          * it below, letting the release do all of the work */
2744         __dlm_lockres_reserve_ast(res);
2745         spin_unlock(&res->spinlock);
2746
2747         /* now flush all the pending asts */
2748         dlm_kick_thread(dlm, res);
2749         /* before waiting on DIRTY, block processes which may
2750          * try to dirty the lockres before MIGRATING is set */
2751         spin_lock(&res->spinlock);
2752         BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2753         res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2754         spin_unlock(&res->spinlock);
2755         /* now wait on any pending asts and the DIRTY state */
2756         wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2757         dlm_lockres_release_ast(dlm, res);
2758
2759         mlog(0, "about to wait on migration_wq, dirty=%s\n",
2760                res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2761         /* if the extra ref we just put was the final one, this
2762          * will pass thru immediately.  otherwise, we need to wait
2763          * for the last ast to finish. */
2764 again:
2765         ret = wait_event_interruptible_timeout(dlm->migration_wq,
2766                    dlm_migration_can_proceed(dlm, res, target),
2767                    msecs_to_jiffies(1000));
2768         if (ret < 0) {
2769                 mlog(0, "woken again: migrating? %s, dead? %s\n",
2770                        res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2771                        test_bit(target, dlm->domain_map) ? "no":"yes");
2772         } else {
2773                 mlog(0, "all is well: migrating? %s, dead? %s\n",
2774                        res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2775                        test_bit(target, dlm->domain_map) ? "no":"yes");
2776         }
2777         if (!dlm_migration_can_proceed(dlm, res, target)) {
2778                 mlog(0, "trying again...\n");
2779                 goto again;
2780         }
2781         /* now that we are sure the MIGRATING state is there, drop
2782          * the unneded state which blocked threads trying to DIRTY */
2783         spin_lock(&res->spinlock);
2784         BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2785         BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2786         res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2787         spin_unlock(&res->spinlock);
2788
2789         /* did the target go down or die? */
2790         spin_lock(&dlm->spinlock);
2791         if (!test_bit(target, dlm->domain_map)) {
2792                 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2793                      target);
2794                 ret = -EHOSTDOWN;
2795         }
2796         spin_unlock(&dlm->spinlock);
2797
2798         /*
2799          * at this point:
2800          *
2801          *   o the DLM_LOCK_RES_MIGRATING flag is set
2802          *   o there are no pending asts on this lockres
2803          *   o all processes trying to reserve an ast on this
2804          *     lockres must wait for the MIGRATING flag to clear
2805          */
2806         return ret;
2807 }
2808
2809 /* last step in the migration process.
2810  * original master calls this to free all of the dlm_lock
2811  * structures that used to be for other nodes. */
2812 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2813                                       struct dlm_lock_resource *res)
2814 {
2815         struct list_head *iter, *iter2;
2816         struct list_head *queue = &res->granted;
2817         int i, bit;
2818         struct dlm_lock *lock;
2819
2820         assert_spin_locked(&res->spinlock);
2821
2822         BUG_ON(res->owner == dlm->node_num);
2823
2824         for (i=0; i<3; i++) {
2825                 list_for_each_safe(iter, iter2, queue) {
2826                         lock = list_entry (iter, struct dlm_lock, list);
2827                         if (lock->ml.node != dlm->node_num) {
2828                                 mlog(0, "putting lock for node %u\n",
2829                                      lock->ml.node);
2830                                 /* be extra careful */
2831                                 BUG_ON(!list_empty(&lock->ast_list));
2832                                 BUG_ON(!list_empty(&lock->bast_list));
2833                                 BUG_ON(lock->ast_pending);
2834                                 BUG_ON(lock->bast_pending);
2835                                 dlm_lockres_clear_refmap_bit(lock->ml.node, res);
2836                                 list_del_init(&lock->list);
2837                                 dlm_lock_put(lock);
2838                         }
2839                 }
2840                 queue++;
2841         }
2842         bit = 0;
2843         while (1) {
2844                 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2845                 if (bit >= O2NM_MAX_NODES)
2846                         break;
2847                 /* do not clear the local node reference, if there is a
2848                  * process holding this, let it drop the ref itself */
2849                 if (bit != dlm->node_num) {
2850                         mlog(0, "%s:%.*s: node %u had a ref to this "
2851                              "migrating lockres, clearing\n", dlm->name,
2852                              res->lockname.len, res->lockname.name, bit);
2853                         dlm_lockres_clear_refmap_bit(bit, res);
2854                 }
2855                 bit++;
2856         }
2857 }
2858
2859 /* for now this is not too intelligent.  we will
2860  * need stats to make this do the right thing.
2861  * this just finds the first lock on one of the
2862  * queues and uses that node as the target. */
2863 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2864                                     struct dlm_lock_resource *res)
2865 {
2866         int i;
2867         struct list_head *queue = &res->granted;
2868         struct list_head *iter;
2869         struct dlm_lock *lock;
2870         int nodenum;
2871
2872         assert_spin_locked(&dlm->spinlock);
2873
2874         spin_lock(&res->spinlock);
2875         for (i=0; i<3; i++) {
2876                 list_for_each(iter, queue) {
2877                         /* up to the caller to make sure this node
2878                          * is alive */
2879                         lock = list_entry (iter, struct dlm_lock, list);
2880                         if (lock->ml.node != dlm->node_num) {
2881                                 spin_unlock(&res->spinlock);
2882                                 return lock->ml.node;
2883                         }
2884                 }
2885                 queue++;
2886         }
2887         spin_unlock(&res->spinlock);
2888         mlog(0, "have not found a suitable target yet! checking domain map\n");
2889
2890         /* ok now we're getting desperate.  pick anyone alive. */
2891         nodenum = -1;
2892         while (1) {
2893                 nodenum = find_next_bit(dlm->domain_map,
2894                                         O2NM_MAX_NODES, nodenum+1);
2895                 mlog(0, "found %d in domain map\n", nodenum);
2896                 if (nodenum >= O2NM_MAX_NODES)
2897                         break;
2898                 if (nodenum != dlm->node_num) {
2899                         mlog(0, "picking %d\n", nodenum);
2900                         return nodenum;
2901                 }
2902         }
2903
2904         mlog(0, "giving up.  no master to migrate to\n");
2905         return DLM_LOCK_RES_OWNER_UNKNOWN;
2906 }
2907
2908
2909
2910 /* this is called by the new master once all lockres
2911  * data has been received */
2912 static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2913                                   struct dlm_lock_resource *res,
2914                                   u8 master, u8 new_master,
2915                                   struct dlm_node_iter *iter)
2916 {
2917         struct dlm_migrate_request migrate;
2918         int ret, status = 0;
2919         int nodenum;
2920
2921         memset(&migrate, 0, sizeof(migrate));
2922         migrate.namelen = res->lockname.len;
2923         memcpy(migrate.name, res->lockname.name, migrate.namelen);
2924         migrate.new_master = new_master;
2925         migrate.master = master;
2926
2927         ret = 0;
2928
2929         /* send message to all nodes, except the master and myself */
2930         while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2931                 if (nodenum == master ||
2932                     nodenum == new_master)
2933                         continue;
2934
2935                 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2936                                          &migrate, sizeof(migrate), nodenum,
2937                                          &status);
2938                 if (ret < 0)
2939                         mlog_errno(ret);
2940                 else if (status < 0) {
2941                         mlog(0, "migrate request (node %u) returned %d!\n",
2942                              nodenum, status);
2943                         ret = status;
2944                 } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
2945                         /* during the migration request we short-circuited
2946                          * the mastery of the lockres.  make sure we have
2947                          * a mastery ref for nodenum */
2948                         mlog(0, "%s:%.*s: need ref for node %u\n",
2949                              dlm->name, res->lockname.len, res->lockname.name,
2950                              nodenum);
2951                         spin_lock(&res->spinlock);
2952                         dlm_lockres_set_refmap_bit(nodenum, res);
2953                         spin_unlock(&res->spinlock);
2954                 }
2955         }
2956
2957         if (ret < 0)
2958                 mlog_errno(ret);
2959
2960         mlog(0, "returning ret=%d\n", ret);
2961         return ret;
2962 }
2963
2964
2965 /* if there is an existing mle for this lockres, we now know who the master is.
2966  * (the one who sent us *this* message) we can clear it up right away.
2967  * since the process that put the mle on the list still has a reference to it,
2968  * we can unhash it now, set the master and wake the process.  as a result,
2969  * we will have no mle in the list to start with.  now we can add an mle for
2970  * the migration and this should be the only one found for those scanning the
2971  * list.  */
2972 int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
2973                                 void **ret_data)
2974 {
2975         struct dlm_ctxt *dlm = data;
2976         struct dlm_lock_resource *res = NULL;
2977         struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2978         struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2979         const char *name;
2980         unsigned int namelen, hash;
2981         int ret = 0;
2982
2983         if (!dlm_grab(dlm))
2984                 return -EINVAL;
2985
2986         name = migrate->name;
2987         namelen = migrate->namelen;
2988         hash = dlm_lockid_hash(name, namelen);
2989
2990         /* preallocate.. if this fails, abort */
2991         mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2992                                                          GFP_NOFS);
2993
2994         if (!mle) {
2995                 ret = -ENOMEM;
2996                 goto leave;
2997         }
2998
2999         /* check for pre-existing lock */
3000         spin_lock(&dlm->spinlock);
3001         res = __dlm_lookup_lockres(dlm, name, namelen, hash);
3002         spin_lock(&dlm->master_lock);
3003
3004         if (res) {
3005                 spin_lock(&res->spinlock);
3006                 if (res->state & DLM_LOCK_RES_RECOVERING) {
3007                         /* if all is working ok, this can only mean that we got
3008                         * a migrate request from a node that we now see as
3009                         * dead.  what can we do here?  drop it to the floor? */
3010                         spin_unlock(&res->spinlock);
3011                         mlog(ML_ERROR, "Got a migrate request, but the "
3012                              "lockres is marked as recovering!");
3013                         kmem_cache_free(dlm_mle_cache, mle);
3014                         ret = -EINVAL; /* need a better solution */
3015                         goto unlock;
3016                 }
3017                 res->state |= DLM_LOCK_RES_MIGRATING;
3018                 spin_unlock(&res->spinlock);
3019         }
3020
3021         /* ignore status.  only nonzero status would BUG. */
3022         ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
3023                                     name, namelen,
3024                                     migrate->new_master,
3025                                     migrate->master);
3026
3027 unlock:
3028         spin_unlock(&dlm->master_lock);
3029         spin_unlock(&dlm->spinlock);
3030
3031         if (oldmle) {
3032                 /* master is known, detach if not already detached */
3033                 dlm_mle_detach_hb_events(dlm, oldmle);
3034                 dlm_put_mle(oldmle);
3035         }
3036
3037         if (res)
3038                 dlm_lockres_put(res);
3039 leave:
3040         dlm_put(dlm);
3041         return ret;
3042 }
3043
3044 /* must be holding dlm->spinlock and dlm->master_lock
3045  * when adding a migration mle, we can clear any other mles
3046  * in the master list because we know with certainty that
3047  * the master is "master".  so we remove any old mle from
3048  * the list after setting it's master field, and then add
3049  * the new migration mle.  this way we can hold with the rule
3050  * of having only one mle for a given lock name at all times. */
3051 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3052                                  struct dlm_lock_resource *res,
3053                                  struct dlm_master_list_entry *mle,
3054                                  struct dlm_master_list_entry **oldmle,
3055                                  const char *name, unsigned int namelen,
3056                                  u8 new_master, u8 master)
3057 {
3058         int found;
3059         int ret = 0;
3060
3061         *oldmle = NULL;
3062
3063         mlog_entry_void();
3064
3065         assert_spin_locked(&dlm->spinlock);
3066         assert_spin_locked(&dlm->master_lock);
3067
3068         /* caller is responsible for any ref taken here on oldmle */
3069         found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3070         if (found) {
3071                 struct dlm_master_list_entry *tmp = *oldmle;
3072                 spin_lock(&tmp->spinlock);
3073                 if (tmp->type == DLM_MLE_MIGRATION) {
3074                         if (master == dlm->node_num) {
3075                                 /* ah another process raced me to it */
3076                                 mlog(0, "tried to migrate %.*s, but some "
3077                                      "process beat me to it\n",
3078                                      namelen, name);
3079                                 ret = -EEXIST;
3080                         } else {
3081                                 /* bad.  2 NODES are trying to migrate! */
3082                                 mlog(ML_ERROR, "migration error  mle: "
3083                                      "master=%u new_master=%u // request: "
3084                                      "master=%u new_master=%u // "
3085                                      "lockres=%.*s\n",
3086                                      tmp->master, tmp->new_master,
3087                                      master, new_master,
3088                                      namelen, name);
3089                                 BUG();
3090                         }
3091                 } else {
3092                         /* this is essentially what assert_master does */
3093                         tmp->master = master;
3094                         atomic_set(&tmp->woken, 1);
3095                         wake_up(&tmp->wq);
3096                         /* remove it from the list so that only one
3097                          * mle will be found */
3098                         list_del_init(&tmp->list);
3099                         /* this was obviously WRONG.  mle is uninited here.  should be tmp. */
3100                         __dlm_mle_detach_hb_events(dlm, tmp);
3101                         ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3102                         mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3103                             "telling master to get ref for cleared out mle "
3104                             "during migration\n", dlm->name, namelen, name,
3105                             master, new_master);
3106                 }
3107                 spin_unlock(&tmp->spinlock);
3108         }
3109
3110         /* now add a migration mle to the tail of the list */
3111         dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3112         mle->new_master = new_master;
3113         /* the new master will be sending an assert master for this.
3114          * at that point we will get the refmap reference */
3115         mle->master = master;
3116         /* do this for consistency with other mle types */
3117         set_bit(new_master, mle->maybe_map);
3118         list_add(&mle->list, &dlm->master_list);
3119
3120         return ret;
3121 }
3122
3123
3124 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3125 {
3126         struct list_head *iter, *iter2;
3127         struct dlm_master_list_entry *mle;
3128         struct dlm_lock_resource *res;
3129         unsigned int hash;
3130
3131         mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
3132 top:
3133         assert_spin_locked(&dlm->spinlock);
3134
3135         /* clean the master list */
3136         spin_lock(&dlm->master_lock);
3137         list_for_each_safe(iter, iter2, &dlm->master_list) {
3138                 mle = list_entry(iter, struct dlm_master_list_entry, list);
3139
3140                 BUG_ON(mle->type != DLM_MLE_BLOCK &&
3141                        mle->type != DLM_MLE_MASTER &&
3142                        mle->type != DLM_MLE_MIGRATION);
3143
3144                 /* MASTER mles are initiated locally.  the waiting
3145                  * process will notice the node map change
3146                  * shortly.  let that happen as normal. */
3147                 if (mle->type == DLM_MLE_MASTER)
3148                         continue;
3149
3150
3151                 /* BLOCK mles are initiated by other nodes.
3152                  * need to clean up if the dead node would have
3153                  * been the master. */
3154                 if (mle->type == DLM_MLE_BLOCK) {
3155                         int bit;
3156
3157                         spin_lock(&mle->spinlock);
3158                         bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3159                         if (bit != dead_node) {
3160                                 mlog(0, "mle found, but dead node %u would "
3161                                      "not have been master\n", dead_node);
3162                                 spin_unlock(&mle->spinlock);
3163                         } else {
3164                                 /* must drop the refcount by one since the
3165                                  * assert_master will never arrive.  this
3166                                  * may result in the mle being unlinked and
3167                                  * freed, but there may still be a process
3168                                  * waiting in the dlmlock path which is fine. */
3169                                 mlog(0, "node %u was expected master\n",
3170                                      dead_node);
3171                                 atomic_set(&mle->woken, 1);
3172                                 spin_unlock(&mle->spinlock);
3173                                 wake_up(&mle->wq);
3174                                 /* do not need events any longer, so detach
3175                                  * from heartbeat */
3176                                 __dlm_mle_detach_hb_events(dlm, mle);
3177                                 __dlm_put_mle(mle);
3178                         }
3179                         continue;
3180                 }
3181
3182                 /* everything else is a MIGRATION mle */
3183
3184                 /* the rule for MIGRATION mles is that the master
3185                  * becomes UNKNOWN if *either* the original or
3186                  * the new master dies.  all UNKNOWN lockreses
3187                  * are sent to whichever node becomes the recovery
3188                  * master.  the new master is responsible for
3189                  * determining if there is still a master for
3190                  * this lockres, or if he needs to take over
3191                  * mastery.  either way, this node should expect
3192                  * another message to resolve this. */
3193                 if (mle->master != dead_node &&
3194                     mle->new_master != dead_node)
3195                         continue;
3196
3197                 /* if we have reached this point, this mle needs to
3198                  * be removed from the list and freed. */
3199
3200                 /* remove from the list early.  NOTE: unlinking
3201                  * list_head while in list_for_each_safe */
3202                 __dlm_mle_detach_hb_events(dlm, mle);
3203                 spin_lock(&mle->spinlock);
3204                 list_del_init(&mle->list);
3205                 atomic_set(&mle->woken, 1);
3206                 spin_unlock(&mle->spinlock);
3207                 wake_up(&mle->wq);
3208
3209                 mlog(0, "%s: node %u died during migration from "
3210                      "%u to %u!\n", dlm->name, dead_node,
3211                      mle->master, mle->new_master);
3212                 /* if there is a lockres associated with this
3213                  * mle, find it and set its owner to UNKNOWN */
3214                 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
3215                 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
3216                                            mle->u.name.len, hash);
3217                 if (res) {
3218                         /* unfortunately if we hit this rare case, our
3219                          * lock ordering is messed.  we need to drop
3220                          * the master lock so that we can take the
3221                          * lockres lock, meaning that we will have to
3222                          * restart from the head of list. */
3223                         spin_unlock(&dlm->master_lock);
3224
3225                         /* move lockres onto recovery list */
3226                         spin_lock(&res->spinlock);
3227                         dlm_set_lockres_owner(dlm, res,
3228                                         DLM_LOCK_RES_OWNER_UNKNOWN);
3229                         dlm_move_lockres_to_recovery_list(dlm, res);
3230                         spin_unlock(&res->spinlock);
3231                         dlm_lockres_put(res);
3232
3233                         /* about to get rid of mle, detach from heartbeat */
3234                         __dlm_mle_detach_hb_events(dlm, mle);
3235
3236                         /* dump the mle */
3237                         spin_lock(&dlm->master_lock);
3238                         __dlm_put_mle(mle);
3239                         spin_unlock(&dlm->master_lock);
3240
3241                         /* restart */
3242                         goto top;
3243                 }
3244
3245                 /* this may be the last reference */
3246                 __dlm_put_mle(mle);
3247         }
3248         spin_unlock(&dlm->master_lock);
3249 }
3250
3251
3252 int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3253                          u8 old_master)
3254 {
3255         struct dlm_node_iter iter;
3256         int ret = 0;
3257
3258         spin_lock(&dlm->spinlock);
3259         dlm_node_iter_init(dlm->domain_map, &iter);
3260         clear_bit(old_master, iter.node_map);
3261         clear_bit(dlm->node_num, iter.node_map);
3262         spin_unlock(&dlm->spinlock);
3263
3264         /* ownership of the lockres is changing.  account for the
3265          * mastery reference here since old_master will briefly have
3266          * a reference after the migration completes */
3267         spin_lock(&res->spinlock);
3268         dlm_lockres_set_refmap_bit(old_master, res);
3269         spin_unlock(&res->spinlock);
3270
3271         mlog(0, "now time to do a migrate request to other nodes\n");
3272         ret = dlm_do_migrate_request(dlm, res, old_master,
3273                                      dlm->node_num, &iter);
3274         if (ret < 0) {
3275                 mlog_errno(ret);
3276                 goto leave;
3277         }
3278
3279         mlog(0, "doing assert master of %.*s to all except the original node\n",
3280              res->lockname.len, res->lockname.name);
3281         /* this call now finishes out the nodemap
3282          * even if one or more nodes die */
3283         ret = dlm_do_assert_master(dlm, res, iter.node_map,
3284                                    DLM_ASSERT_MASTER_FINISH_MIGRATION);
3285         if (ret < 0) {
3286                 /* no longer need to retry.  all living nodes contacted. */
3287                 mlog_errno(ret);
3288                 ret = 0;
3289         }
3290
3291         memset(iter.node_map, 0, sizeof(iter.node_map));
3292         set_bit(old_master, iter.node_map);
3293         mlog(0, "doing assert master of %.*s back to %u\n",
3294              res->lockname.len, res->lockname.name, old_master);
3295         ret = dlm_do_assert_master(dlm, res, iter.node_map,
3296                                    DLM_ASSERT_MASTER_FINISH_MIGRATION);
3297         if (ret < 0) {
3298                 mlog(0, "assert master to original master failed "
3299                      "with %d.\n", ret);
3300                 /* the only nonzero status here would be because of
3301                  * a dead original node.  we're done. */
3302                 ret = 0;
3303         }
3304
3305         /* all done, set the owner, clear the flag */
3306         spin_lock(&res->spinlock);
3307         dlm_set_lockres_owner(dlm, res, dlm->node_num);
3308         res->state &= ~DLM_LOCK_RES_MIGRATING;
3309         spin_unlock(&res->spinlock);
3310         /* re-dirty it on the new master */
3311         dlm_kick_thread(dlm, res);
3312         wake_up(&res->wq);
3313 leave:
3314         return ret;
3315 }
3316
3317 /*
3318  * LOCKRES AST REFCOUNT
3319  * this is integral to migration
3320  */
3321
3322 /* for future intent to call an ast, reserve one ahead of time.
3323  * this should be called only after waiting on the lockres
3324  * with dlm_wait_on_lockres, and while still holding the
3325  * spinlock after the call. */
3326 void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3327 {
3328         assert_spin_locked(&res->spinlock);
3329         if (res->state & DLM_LOCK_RES_MIGRATING) {
3330                 __dlm_print_one_lock_resource(res);
3331         }
3332         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3333
3334         atomic_inc(&res->asts_reserved);
3335 }
3336
3337 /*
3338  * used to drop the reserved ast, either because it went unused,
3339  * or because the ast/bast was actually called.
3340  *
3341  * also, if there is a pending migration on this lockres,
3342  * and this was the last pending ast on the lockres,
3343  * atomically set the MIGRATING flag before we drop the lock.
3344  * this is how we ensure that migration can proceed with no
3345  * asts in progress.  note that it is ok if the state of the
3346  * queues is such that a lock should be granted in the future
3347  * or that a bast should be fired, because the new master will
3348  * shuffle the lists on this lockres as soon as it is migrated.
3349  */
3350 void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3351                              struct dlm_lock_resource *res)
3352 {
3353         if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3354                 return;
3355
3356         if (!res->migration_pending) {
3357                 spin_unlock(&res->spinlock);
3358                 return;
3359         }
3360
3361         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3362         res->migration_pending = 0;
3363         res->state |= DLM_LOCK_RES_MIGRATING;
3364         spin_unlock(&res->spinlock);
3365         wake_up(&res->wq);
3366         wake_up(&dlm->migration_wq);
3367 }